Validation in JavaScript

[kprasanthmca]

How to validate usernames in JavaScript?

[AricC]

What kind of username are you trying to validate? Do you want to simply validate that one exists? Or do you need a regex?

[kprasanthmca]

Allow alphabets,numbers and underscore in username

[iam_clint]

//alert on finding all letters
    var noalpha = /^[a-zA-Z]*$/;
if (noalpha.test(document.formname.fieldname.value)) {
     alert("Please enter at least one number in the \"username\" field.");
     return false;
}
 
//alert on finding all numbers
var nonums = /^[0-9]*$/;
if (nonums.test(document.formname.fieldname.value)) {
     alert("Please enter at least one letter in the \"username\" field.");
     return false;
}
 

heres a small snippet to help get you started