Output Display Possibilities in Javascript
Table of Content:
JavaScript can display data in different ways:
- Writing into an HTML element, using
innerHTML. - Writing into the HTML output using
document.write(). - Writing into an alert box, using
window.alert(). - Writing into the browser console, using
console.log().
1. Using innerHTML
To access an HTML element, JavaScript can use the document.getElementById(id) method.
The id attribute defines the HTML element. The innerHTML property defines the HTML content:
<!DOCTYPE html> <html> <body> <h1> Welcome to My First Web Page </h1> <p> This is My First Paragraph </p> <p id="demo"></p> <script> document.getElementById("demo").innerHTML = 10 + 11; </script> </body> </html>
Changing the innerHTML property of an HTML element is a common way to display data in HTML.
Using document.write()
For testing purposes, it is convenient to use document.write():
<!DOCTYPE html> <html> <body> <h1> Welcome to My First Web Page </h1> <p> This is My first paragraph. </p> <script> document.write(10 + 11); </script> </body> </html>
Using document.write() after an HTML document is loaded, will delete all existing HTML
<!DOCTYPE html> <html> <body> <h1> Welcome to My First Web Page </h1> <p> This is My first paragraph. </p> <button type="button" onclick="document.write(10 + 11)">Try it</button> </body> </html>
The document.write() method should only be used for testing.
Using window.alert()
You can use an alert box to display data:
Example
<!DOCTYPE html> <html> <body> <h1> Welcome to My First Web Page </h1> <p> This is My first paragraph. </p> <script> window.alert(10+ 11); </script> </body> </html>
Using console.log()
For debugging purposes, you can use the console.log() method to display data.
<!DOCTYPE html> <html> <body> <script> console.log(10 + 11); </script> </body> </html>