Can we read excel file in javascript?

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 :

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

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.

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 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 diferent plugin in it which is for .xls

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

1. We included difference JS plugin file :
2. Changed few lines of code for 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]);?

Rest of the code remains 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.

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