If it's C then we can just get output with printf. If it's Java then system.out.println and if it's python then just print. But with JavaScript we have 4 different options to print the output.

  1. innerHTML will write output in HTML element
  2. document.write() will write into HTML output
  3. window.alert() will show output in alert box
  4. console.log() will write output in browser console.

Let's look at those 4 ways one by one.

1. innerHTML

This is the most common method of displaying data (output).

To access the HTML element we use document.getElementById (name of the id in html) method. We assign 'id' to HTML element and innerHTML is the content of that element.

Take a look at the example below.

<body> <h1>.innerHTML Example</h1> <p id="example1"></p> <script> document.getElementById("example1").innerHTML = "innerHTML example"; </script> </body> /* Outptut */ innerHTML example

Checkout the examples in the DEMO Link.

2. document.write()

<script> document.write("document.write Example"); </script>

The problem with document.write is that if you call it after the document is loaded, then it'll delete all the existing HTML code and write the new one with the new output.

3. window.alert()

We can use alert box to display output but it's not useful in all situations. It's really useful for warnings only. For e.g. if user enters text instead of number. Take a look at the example below...

<body> <button onclick="example3()">Click to get the alert</button> <script> function example3(){ window.alert("You got me!"); } </script> </body>

It will give you an alert when you click on the button.

4. console.log()

We use console.log() mostly for debugging purposes only. You really can't see the output on your browser screen. Take a look...

<script> console.log("I am console.log Example"); </script> In Google Chrome, you have to right click on the page and then click on 'inspect' and then go to 'console' to see the output.

Checkout the DEMO


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