Some times we may come across requirements like, we need to validate the ASPX validation controls in java script. For example, on a page we have both ASPX controls like text boxes, drop down lists etc and along with them some html text boxes or select drop down, then we need to validate the form. When you hit submit we need to validate whether form is valid or not. As we use ASP.NET validation controls for .NEt controls, the validation fires automatically. But, what about HTML controls? We need to write our own logic to validate the controls. So, If you want to tell this form is valid then you need some logic to validate both asp.net server side controls and html controls and both are valid then only say form is valid. Take a look at here to solve that problem.