JavaScript regular expression validation for domain name?

Question

How to check a valid domain name and username with regular expression in JavaScript?

function validate()
{
    var         


        

Answer 1

Don't mix up the RegExp constructor with regex literals. Use either

/^[a-zA-Z0-9._-]+\\[a-zA-Z0-9.-]$/

or

new RegExp("^[a-zA-Z0-9._-]+\\\\[a-zA-Z0-9.-]$");

Not sure what the backslash does in there, btw. Did you want to match a dot? In literal, use \., in string use \\..