How to use Ejs in JavaScript ?

Last Updated : 08 Jan, 2025

EJS or Embedded Javascript Templating is a templating engine used by Node.js. The template engine helps to create an HTML template with minimal code. Also, it can inject data into the HTML template on the client side and produce the final HTML.

Installation Steps

Install the module using the following command:

npm install ejs --save

Note:

In the commands above, "npm" stands for the Node Package Manager, which is where all the dependencies are stored. The
"--save" flag is no longer needed after Node 5.0.0, as all the modules we install will now be added to dependencies automatically.

To start, we need to set EJS as our templating engine with Express. Express is a Node.js web application server framework designed for building single-page, multi-page, and hybrid web applications. It has become the standard server framework for Node.js.

Data passed from the server is sent to the EJS file and then we can access that data using the below line and it will give that data to h, p, or another text tag.

<%= data %>

If we want to use this data for normal js operations like if-else and loops or other programming statements we can write it in the following form:

<% if(data == "1"){%>
<h5>Cricket</h5>
<%}else{%>
<h5>Football</h5>
<%}%>

Now to access that data in the script tag of the EJS file or the .js file all you need to do is to pass that data in another variable as below:

let data = '<%-data%>'

Now you can perform any operation on the data variable that has the same value as the EJS passed data variable.

Example: Implementation to use EJS in our project.

javascript

// Filename - index.js 
// Set express as Node.js web application 
// server framework. 

// Install it using 'npm install express' command 
// and require like this:
let express = require('express'); 
let app = express(); 
  
// Set EJS as templating engine 
app.set('view engine', 'ejs'); 

app.get("/", function(req, res) {  
  res.render("home", {name:'Chris Martin'});
});
  
// Server setup
app.listen(3000, function(req, res) {
  console.log("Connected on port:3000");
});

The default behaviour of EJS is that it looks into the ‘views’ folder for the templates to render. So, let’s make a ‘views’ folder in our main node project folder and make a file named “home.ejs” which is to be served on some desired request in our node project.

HTML

<!-- home.ejs -->

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" 
          content="width=device-width, initial-scale=1.0">
</head>

<body>
        <!-- Text from EJS variable 
            passed from server -->
        <h2>
            Text from EJS variable passed
            from server is =
        </h2>
        <h2 style="color:red">
            <%=name%>
        </h2>
        <br>

        <!-- Text from EJS variable 
            passed from script tag -->
        <h2 style="color: blue;">
            Text from EJS variable passed
            from script tag =
        </h2>
        <h2 style="color: blue;" id="text_from_script">
        </h2>
        <br>

        <!-- Text from EJS variable passed 
            from script tag after manipulation -->
        <h2 style="color: green;">
            Text from EJS variable passed from
            script tag after manipulation =
        </h2>
        <h2 style="color: green;" 
            id="text_from_script_manipulated">
        </h2>

    <script>
        let name = '<%-name%>'
        let heading = document
            .getElementById('text_from_script');

        heading.innerText = name;
        name = "Mr. " + name;
        let heading_man = document.getElementById(
            'text_from_script_manipulated');
        heading_man.innerText = name; 
    </script>
</body>

</html>

The "name" variable has been passed from the server to the 'name.ejs' file and displayed using an h2 tag. To use the "name" variable in the script tag, all we did was declare a variable and assign the EJS variable to the declared variable using:

let name = '<%-name%>'

Step to Run Application: Run the application using the following command from the root directory of the project