How to implement Javascript on webpages


alert("hello world");


kindly tell me how to implement pop up message in webpages ?


JavaScript pop-up dialogs are best reserved for debugging, and not web facing pages. However, in the odd case, it can be useful. The better approach, which you will learn later on, is to use the web page itself to communicate with the user. For now, though,

// some code
alert("Hello World!");

At present we don't have any context so I cannot really expand on this answer. Rather than get ahead of the game, continue with the track and come back to this question when you have the skills necessary to implement JS in a webpage.