Would like to know the concept behind the working of the URL below:
www.tradeshows.tradeindia.com/musician-expo2013/register.html
If any user clicks on the submit button without filling any information then a javascript pop up appears and all the important fields that has to displayed is shown one by one, I am aware about alert function of javascript but not aware to validate multiple textbox's using javascript.How to achieve this?
In the above mentioned URL directly click on the the submit button, you will understand what exactly I want.