Cross-browser javascript IsNumeric() method

To make a Client-side numeric textbox control using javascript is a common task in web development. Numeric checking may varried based on business logic. Like positive int, positive decimal, signed int or signed decimal. In my post i will try to focus on each requirement plus cross-browser compatibility. Here i will try to describe the script for 4 different methods for 4 business cases. Choose what you need. 4 cross-browser supported Client Side javascript IsNumeric() methods are as follows: