К input data from excel

The weird characters you got from reading the Excel file from the FileReader API comes from the structure of the file that differs a lot from a text file.

So reading it as text with the FileReader API will give those weirds character as a result.

What you can do is to use the FileReader API to read it as a binary string.
At this point if you try to log that binary string you will also get weirds characters.

In order to get your file content you need to parse that binary string to extract the data it contains. This can be done quite easily using SheetJS.

import { read, writeFileXLSX, utils } from "https://cdn.sheetjs.com/xlsx-0.18.7/package/xlsx.mjs";

const workbook = read(data, {
       type:'binary',
});

data is the binary string resulting from reading an Excel file as a binary string with the FileReader API.

workbook is an object that contains all the data of your file.

The workbook.Sheets instruction will give you access to all the sheets that are in the file.

workbook.Sheets.sheet1 will give you access to the content of the first sheet of the file.

All the related arrays are from the {key:value} type.

The content of a sheet accessed this way is a single dimension object array wich contains all the cells of the sheet starting from the first cell of the header to the last cell wich contains data.
Each of those cells has a key like this 'A1', 'B250', 'J3'

This array also have two more entries with those keys '!margin' and '!ref':
'!margin' refers to cells margins so it may not represent any interest.
'!ref' is more interesting as it contains the plage of cells containing data wich is a string
like this 'A1:J215' from it you could get the amount of lines or the char of the last column.

If you want more informations you could check the SheetJS documentation and there is a more detailed example here : How to read an excel file contents on client side?

Note :
If you want to use this import statement in an html page you’ll need to do it inside those scripts tags : <script type="module" defer> ... </script>

Here is a codepen where you can test this method. There’s only the most basic method. There are some shorter ways to do the same by using the SheetJS utils functions to convert directly the sheet content to another format.

In the previous post, I have explained how we can read csv file using javascript and HTML 5 filereader, now in this post, I have explained how we can use external library like xlsx to parse or read excel file using javascript and show it’s contents in HTML table. When file is uploaded using Javascript, it is read as Binary string initially, and then binary data is read using xlsx plugin.

Read XLSX using Javascript

Let’s beging by adding simple HTML file input and button to upload file

<input type="file" id="fileUpload" />
<input type="button" id="upload" value="Upload" onclick="UploadProcess()" />
<br/>

<div id="ExcelTable"></div>

I have also included empty HTML div to create table inside it from our Excel file.

Now, we will create the function to upload the file and process the Excel file to get data from it and convert it into HTML table.

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.13.5/xlsx.full.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.13.5/jszip.js"></script>
<script type="text/javascript">
    function UploadProcess() {
        //Reference the FileUpload element.
        var fileUpload = document.getElementById("fileUpload");
 
        //Validate whether File is valid Excel file.
        var regex = /^([a-zA-Z0-9s_\.-:])+(.xls|.xlsx)$/;
        if (regex.test(fileUpload.value.toLowerCase())) {
            if (typeof (FileReader) != "undefined") {
                var reader = new FileReader();
 
                //For Browsers other than IE.
                if (reader.readAsBinaryString) {
                    reader.onload = function (e) {
                        GetTableFromExcel(e.target.result);
                    };
                    reader.readAsBinaryString(fileUpload.files[0]);
                } else {
                    //For IE Browser.
                    reader.onload = function (e) {
                        var data = "";
                        var bytes = new Uint8Array(e.target.result);
                        for (var i = 0; i < bytes.byteLength; i++) {
                            data += String.fromCharCode(bytes[i]);
                        }
                        GetTableFromExcel(data);
                    };
                    reader.readAsArrayBuffer(fileUpload.files[0]);
                }
            } else {
                alert("This browser does not support HTML5.");
            }
        } else {
            alert("Please upload a valid Excel file.");
        }
    };
    function GetTableFromExcel(data) {
        //Read the Excel File data in binary
        var workbook = XLSX.read(data, {
            type: 'binary'
        });
 
        //get the name of First Sheet.
        var Sheet = workbook.SheetNames[0];
 
        //Read all rows from First Sheet into an JSON array.
        var excelRows = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[Sheet]);
 
        //Create a HTML Table element.
        var myTable  = document.createElement("table");
        myTable.border = "1";
 
        //Add the header row.
        var row = myTable.insertRow(-1);
 
        //Add the header cells.
        var headerCell = document.createElement("TH");
        headerCell.innerHTML = "Id";
        row.appendChild(headerCell);
 
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Name";
        row.appendChild(headerCell);
 
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Country";
        row.appendChild(headerCell);
        
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Age";
        row.appendChild(headerCell);
        
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Date";
        row.appendChild(headerCell);
         
         headerCell = document.createElement("TH");
        headerCell.innerHTML = "Gender";
        row.appendChild(headerCell);
 
 
        //Add the data rows from Excel file.
        for (var i = 0; i < excelRows.length; i++) {
            //Add the data row.
            var row = myTable.insertRow(-1);
 
            //Add the data cells.
            var cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Id;
 
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Name;
 
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Country;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Age;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Date;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Gender;
        }
        
 
        var ExcelTable = document.getElementById("ExcelTable");
        ExcelTable.innerHTML = "";
        ExcelTable.appendChild(myTable);
    };
</script>

In the above Javascript code, we are first adding references of XLSX plugin files and then adding two functions

1. UploadProcess: Uploads the file on button click and convert it into Binary data, it also check if Browser is IE then process accordingly to convert file into binary.
2. ProcessExcel: this function takes the binary data, reads the Sheet name, create Table element and append each row in it.

I have explained lines of code using Comment.

Suppose our sample Excel file looks like this

So, if use the above code in HTML/Javascript, output will be as below

Here is the fiddle link https://jsfiddle.net/abj98oxf/3/

Read XLS file using Javascript

In a Similar way, we can read .xls (excel) file also and show it in HTML table, I will repeat the same code, just few lines of code is different, also we will be using different plugin in it which is for .xls

<input type="file" id="fileUpload" />
<input type="button" id="upload" value="Upload" onclick="UploadProcess()" />
<br/>

<div id="ExcelTable"></div>

<script src="https://cdnjs.cloudflare.com/ajax/libs/xls/0.7.4-a/xls.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.13.5/jszip.js"></script>
<script type="text/javascript">
    function UploadProcess() {
        //Reference the FileUpload element.
        var fileUpload = document.getElementById("fileUpload");
 
        //Validate whether File is valid Excel file.
        var regex = /^([a-zA-Z0-9s_\.-:])+(.xls|.xlsx)$/;
        if (regex.test(fileUpload.value.toLowerCase())) {
            if (typeof (FileReader) != "undefined") {
                var reader = new FileReader();
 
                //For Browsers other than IE.
                if (reader.readAsBinaryString) {
                    reader.onload = function (e) {
                        GetTableFromExcel(e.target.result);
                    };
                    reader.readAsBinaryString(fileUpload.files[0]);
                } else {
                    //For IE Browser.
                    reader.onload = function (e) {
                        var data = "";
                        var bytes = new Uint8Array(e.target.result);
                        for (var i = 0; i < bytes.byteLength; i++) {
                            data += String.fromCharCode(bytes[i]);
                        }
                        GetTableFromExcel(data);
                    };
                    reader.readAsArrayBuffer(fileUpload.files[0]);
                }
            } else {
                alert("This browser does not support HTML5.");
            }
        } else {
            alert("Please upload a valid Excel file.");
        }
    };
    function GetTableFromExcel(data) {
        //Read the Excel File data in binary
        var cfb = XLS.CFB.read(data, {type: 'binary'});
        var workbook = XLS.parse_xlscfb(cfb);
 
        //get the name of First Sheet.
        var Sheet = workbook.SheetNames[0];
 
        //Read all rows from First Sheet into an JSON array.
        var excelRows = XLS.utils.sheet_to_row_object_array(workbook.Sheets[Sheet]);
 
        //Create a HTML Table element.
        var myTable  = document.createElement("table");
        myTable.border = "1";
 
        //Add the header row.
        var row = myTable.insertRow(-1);
 
        //Add the header cells.
        var headerCell = document.createElement("TH");
        headerCell.innerHTML = "Id";
        row.appendChild(headerCell);
 
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Name";
        row.appendChild(headerCell);
 
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Country";
        row.appendChild(headerCell);
        
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Age";
        row.appendChild(headerCell);
        
        headerCell = document.createElement("TH");
        headerCell.innerHTML = "Date";
        row.appendChild(headerCell);
         
         headerCell = document.createElement("TH");
        headerCell.innerHTML = "Gender";
        row.appendChild(headerCell);
 
 
        //Add the data rows from Excel file.
        for (var i = 0; i < excelRows.length; i++) {
            //Add the data row.
            var row = myTable.insertRow(-1);
 
            //Add the data cells.
            var cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Id;
 
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Name;
 
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Country;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Age;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Date;
            
            cell = row.insertCell(-1);
            cell.innerHTML = excelRows[i].Gender;
        }
        
 
        var ExcelTable = document.getElementById("ExcelTable");
        ExcelTable.innerHTML = "";
        ExcelTable.appendChild(myTable);
    };
</script>

The XLS file upload code is the same as .XLSX one was, here are the changes

1. We included difference JS plugin file : <script src=»https://cdnjs.cloudflare.com/ajax/libs/xls/0.7.4-a/xls.js»></script>
2. Changed a few lines of code for the function «GetTableFromExcel»

          //Read the Excel File data in binary
            var cfb = XLS.CFB.read(data, {type: 'binary'});
           var workbook = XLS.parse_xlscfb(cfb);
    
           //get the name of First Sheet.
           var Sheet = workbook.SheetNames[0];
    
           //Read all rows from First Sheet into an JSON array.
           var excelRows = XLS.utils.sheet_to_row_object_array(workbook.Sheets[Sheet]);?

The rest of the code remains the same.

Here is the working fiddle link: https://jsfiddle.net/y3tx8wk4/1/

Note: You need to pass .xls file in this code to make it work.

Convert Excel to JSON using Javascript

You can also upload excel and then convert it to JSON data and proceed with it further.

<form enctype="multipart/form-data">
  <input id="upload" type=file name="files[]">
</form>

<textarea class="form-control" rows=35 cols=120 id="xlx_json"></textarea>



<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
  document.getElementById('upload').addEventListener('change', handleFileSelect, false);
  var ExcelToJSON = function() {

    this.parseExcel = function(file) {
      var reader = new FileReader();

      reader.onload = function(e) {
        var data = e.target.result;
        var workbook = XLSX.read(data, {
          type: 'binary'
        });
        workbook.SheetNames.forEach(function(sheetName) {
          // Here is your object
          var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
          var json_object = JSON.stringify(XL_row_object);
          console.log(JSON.parse(json_object));
          jQuery('#xlx_json').val(json_object);
        })
      };

      reader.onerror = function(ex) {
        console.log(ex);
      };

      reader.readAsBinaryString(file);
    };
  };

  function handleFileSelect(evt) {

    var files = evt.target.files; // FileList object
    var xl2json = new ExcelToJSON();
    xl2json.parseExcel(files[0]);
  }
</script>

Here is the fiddle: https://jsfiddle.net/aszchkr0/ using which you can test the above code, just to search excel file and once value is changed you will find JSON result in textarea.

In the above code, we are reading excel using XLSX plugin, then we loop through each sheet and get XL row object and further convert it to JSON.

You may also like to read:

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Convert seconds to hh:mm:ss using Javascript

Uncaught Error: «Cannot use import statement outside a module»

Encrypt and Decrypt string in Javascript

Email validation using jQuery (Various Methods)

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In this tutorial you can find how to read excel file using JavaScript and display excel sheet data on web page in HTML table format using JavaScript. In previous, one of our tutorial, in which we have already seen how to convert HTML table data into Excel file by using SheetJS library. Now in this tutorial also we will use SheetJS JavaScript library and by using JavaScript library, we will convert Excel file data to HTML table and display on web page. Here under this tutorial, we will not use jQuery and Ajax server side script for fetch data from excel and display on web page. Now lets start seeing it!

First we have to include Bootstrap Stylesheet and SheetJS library link at header of our HTML page.

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">

<script type="text/javascript" src="https://unpkg.com/xlsx@0.15.1/dist/xlsx.full.min.js"></script>

After this under this HTML page, we have to create one file tag for select file excel from local computer.

<input type="file" id="excel_file" />

And below this file, we have to create one division tag for display excel sheet data on web page in HTML table format.

<div id="excel_data" class="mt-5"></div>

Next we have to move on write JavaScript code, so first store file tag property under one variable.

const excel_file = document.getElementById('excel_file');

Next we have to write javascript code on change event, so when user have select file from local computer using file tag, then javascript code must be execute.

excel_file.addEventListener('change', (event) => {

});

Under this change event code first we want to check selected file format is .xls or .xlsx. If selected file is not excel file then it will display error on web page, and if select file is excel then it will proceed for display excel file data on web page.

if(!['application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'application/vnd.ms-excel'].includes(event.target.files[0].type))
    {
        document.getElementById('excel_data').innerHTML = '<div class="alert alert-danger">Only .xlsx or .xls file format are allowed</div>';

        excel_file.value = '';

        return false;
    }

After check validation error, now read the file using FileReader object. Here file must be read ads ArrayBuffer by pass the file object using event.target.files[0].

var reader = new FileReader();

reader.readAsArrayBuffer(event.target.files[0]);

IF the selected file is proper excel file then we need to convert what we have got from FileReader object to Unit8Array object by passing Filereader result into Unit8Array constructor.

var data = new Uint8Array(reader.result);

Next we have pass this Unit8Array data in SheetJS read() function, and it will return selected excel workbook object.

var work_book = XLSX.read(data, {type:'array'});

After getting workbook object, next we have to get sheet name of selected excel file. So here SheetNames variable will return sheet name in array format.

var sheet_name = work_book.SheetNames;

Once we have get sheet name, now we want to get first sheet data in JSON format, so this we can get by SheetJS sheet_to_json() function by passing workbook first sheet name.

var sheet_data = XLSX.utils.sheet_to_json(work_book.Sheets[sheet_name[0]], {header:1});

Once we have get first sheet data in JSON format, next we have to simply write JavaScript code and convert that JSON data into HTML format and display under division tag wih id excel_data. So it will display excel file data on web page in HTML table format.

        if(sheet_data.length > 0)
        {
            var table_output = '<table class="table table-striped table-bordered">';

            for(var row = 0; row < sheet_data.length; row++)
            {

                table_output += '<tr>';

                for(var cell = 0; cell < sheet_data[row].length; cell++)
                {

                    if(row == 0)
                    {

                        table_output += '<th>'+sheet_data[row][cell]+'</th>';

                    }
                    else
                    {

                        table_output += '<td>'+sheet_data[row][cell]+'</td>';

                    }

                }

                table_output += '</tr>';

            }

            table_output += '</table>';

            document.getElementById('excel_data').innerHTML = table_output;
        }

So once you have follow all above steps then you can check ouput in browser. So when we have select excel file then it will display excel sheet data on web page in HTML table format without refresh of web page. So in this tutorial, we have seen how to convert Excel file to HTML table at client-side by using SheetJS JavaScript library at client-side. Below you can find complete source code.

Full Source Code

<!DOCTYPE HTML>
<html>
<head>
	<meta charset="utf-8" />
	<title>Convert Excel to HTML Table using JavaScript</title>
	<meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">

    <script type="text/javascript" src="https://unpkg.com/xlsx@0.15.1/dist/xlsx.full.min.js"></script>
</head>
<body>
    <div class="container">
    	<h2 class="text-center mt-4 mb-4">Convert Excel to HTML Table using JavaScript</h2>
    	<div class="card">
    		<div class="card-header"><b>Select Excel File</b></div>
    		<div class="card-body">
    			
                <input type="file" id="excel_file" />

    		</div>
    	</div>
        <div id="excel_data" class="mt-5"></div>
    </div>
</body>
</html>

<script>

const excel_file = document.getElementById('excel_file');

excel_file.addEventListener('change', (event) => {

    if(!['application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'application/vnd.ms-excel'].includes(event.target.files[0].type))
    {
        document.getElementById('excel_data').innerHTML = '<div class="alert alert-danger">Only .xlsx or .xls file format are allowed</div>';

        excel_file.value = '';

        return false;
    }

    var reader = new FileReader();

    reader.readAsArrayBuffer(event.target.files[0]);

    reader.onload = function(event){

        var data = new Uint8Array(reader.result);

        var work_book = XLSX.read(data, {type:'array'});

        var sheet_name = work_book.SheetNames;

        var sheet_data = XLSX.utils.sheet_to_json(work_book.Sheets[sheet_name[0]], {header:1});

        if(sheet_data.length > 0)
        {
            var table_output = '<table class="table table-striped table-bordered">';

            for(var row = 0; row < sheet_data.length; row++)
            {

                table_output += '<tr>';

                for(var cell = 0; cell < sheet_data[row].length; cell++)
                {

                    if(row == 0)
                    {

                        table_output += '<th>'+sheet_data[row][cell]+'</th>';

                    }
                    else
                    {

                        table_output += '<td>'+sheet_data[row][cell]+'</td>';

                    }

                }

                table_output += '</tr>';

            }

            table_output += '</table>';

            document.getElementById('excel_data').innerHTML = table_output;
        }

        excel_file.value = '';

    }

});

</script>