Javascript Display Excel In HTML Table (Simple Example)

Welcome to a tutorial on how to display an Excel file in an HTML table in Javascript. Need to open an Excel file and “convert” it into an HTML table? Yes, that is possible with modern Javascript. No server-side scripts, no uploading involved. Read on for the example!

 

 

TABLE OF CONTENTS

 

 

EXAMPLE CODE DOWNLOAD

Source code on GitHub Gist | Example on CodePen

Just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

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TUTORIAL VIDEO

 

PART 1) DUMMY EXCEL FILE

NAME	EMAIL
Jo Doe	jo@doe.com
Job Doe	job@doe.com
Joe Doe	joe@doe.com
Jog Doe	jog@doe.com
Joh Doe	joh@doe.com
Joi Doe	joi@doe.com
Jol Doe	jol@doe.com
Jon Doe	jon@doe.com
Jou Doe	jou@doe.com
Joy Doe	joy@doe.com

First, let us start with the Excel file… There is nothing “special” here, this is just a list of dummy users.

 

 

PART 2) HTML PAGE

<!-- (A) JAVASCRIPT -->
<!-- https://sheetjs.com/ -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.18.5/xlsx.full.min.js"></script>
<script defer src="3-excel-table.js"></script>
 
<!-- (B) FILE PICKER -->
<input type="file" id="demoA" accept=".xls,.xlsx">
 
<!-- (C) EMPTY TABLE -->
<table id="demoB"></table>

Next, the HTML page itself should be pretty self-explanatory too.

1. Javascript does not have native functions to read Excel files, so we using a library called “SheetJS” here. Links to their full documentation are in the extras section below.
2. Just a normal <input type="file"> file input field, restricted to accept Excel files only. But take note, SheetJS can actually open CSV and ODT files too.
3. An empty <table> to display the Excel file.

 

 

PART 3) EXCEL TO HTML TABLE

document.getElementById("demoA").onchange = (evt) => {
  // (A) NEW FILE READER
  var reader = new FileReader();
 
  // (B) ON FINISH LOADING
  reader.addEventListener("loadend", (evt) => {
    // (B1) GET HTML TABLE
    var table = document.getElementById("demoB");
    table.innerHTML = "";
 
    // (B2) GET THE FIRST WORKSHEET
    var workbook = XLSX.read(evt.target.result, {type: "binary"}),
        worksheet = workbook.Sheets[workbook.SheetNames[0]],
        range = XLSX.utils.decode_range(worksheet["!ref"]);
 
    // (B3) READ EXCEL CELLS & INSERT ROWS/COLUMNS
    for (let row=range.s.r; row<=range.e.r; row++) {
      let r = table.insertRow();
      for (let col=range.s.c; col<=range.e.c; col++) {
        let c = r.insertCell(),
        xcell = worksheet[XLSX.utils.encode_cell({r:row, c:col})];
        c.innerHTML = xcell.v;
      }
    }
  });
 
  // (C) START - READ SELECTED EXCEL FILE
  reader.readAsArrayBuffer(evt.target.files[0]);
};

Lastly, not going to explain this line-by-line. But when the user picks a file with <input type="file">:

1. We create a new FileReader() to read the first worksheet of the selected Excel file.
2. Use SheetJS to loop through the rows and columns, and generate the HTML table.
3. Read the selected Excel file as an array buffer. This effectively starts (B).

 

 

EXTRA) READING MULTIPLE WORKSHEETS

<!-- (C) EMPTY CONTAINER -->
<div id="demoB"></div>

Create an empty container instead of a table.

// (B) ON FINISH LOADING
reader.addEventListener("loadend", evt => {
  // (B1) GET DIV CONTAINER
  var div = document.getElementById("demoB");
  div.innerHTML = "";
 
  // (B2) LOOP THROUGH ALL WORKSHEETS
  var workbook = XLSX.read(evt.target.result, {type: "binary"});
  for (let worksheet of Object.values(workbook.Sheets)) {
    // (B2-1) CREATE TABLE & APPEND TO DIV CONTAINER
    var table = document.createElement("table");
    div.appendChild(table);
 
    // (B2-2) READ EXCEL CELLS & INSERT ROWS/COLUMNS
    var range = XLSX.utils.decode_range(worksheet["!ref"]);
    for (let row=range.s.r; row<=range.e.r; row++) {
      let r = table.insertRow();
      for (let col=range.s.c; col<=range.e.c; col++) {
        let c = r.insertCell(),
        xcell = worksheet[XLSX.utils.encode_cell({r:row, c:col})];
        c.innerHTML = xcell.v;
      }
    }
  }
});

Instead of reading the first worksheet only, loop through all the worksheets – Generate the HTML table, rows, and cells as usual.

 

 

COMPATIBILITY CHECKS

• Arrow Functions – CanIUse
• File Reader – CanIUse

This example works on all modern “Grade A” browsers.

 

LINKS & REFERENCES

• SheetJS – GitHub
• Javascript Read Excel File Into Array/JSON – Code Boxx
• How To Read Files In Javascript – Code Boxx