How do you validate a number in java script?

Answer 1

JavaScript is written within an HTML page (or in an external .js file but technically it's still part of the page) and adds special effects to that page. W3Schools has some really good tutorials. You can find the link in the related links.

You can write JavaScript in Notepad! However most people prefer an IDE. I like Komodo Edit, personally. You can find a link for Komodo in the Related Links.

Answer 2

Javascript validation is a situation where the Javascript language is used to check on forms and fields in a web document and ensure that only the proper input is contained in them. Some validation is done at the time of typing, but often it is checked when a form is submitted.

Answer 3

Testing and debugging javascript as a "compile on runtime" kind of language can be a pain since one have to test each feature of the program individually to see if there are errors.

Using a JavaScript console (either the built in console in Google Chrome (Ctrl+Shift+J) or FireBug extension to Firefox) can be very useful as you will get somehow meaningful error messages. Or at least get told where an error occurs.

Another kind of tool is Douglas Corckfords jslint or the Google Closure Tools.

(The Google JavaScript Style guide will probably be to big help when working with either one of these.)

For links to these tools, please see the related links.

Answer 4

We can validate a number by using isNaN() function in javascript, if this function returns false the given value is a number otherwise its not a number.