Unfortunately regular expressions are something I know nothing about.

I am trying to validate an email address using javascript and this is what I am using:

var expression = /^[a-zA-Z0-9]+[a-zA-Z0-9_.-]+[a-zA-Z0-9_-]+@[a-zA-Z0-9]+[a-zA-Z0-9.-]+[a-zA-Z0-9]+.[a-z]{2,4}$/;

However this doesn't allow for someone to use a filter on a gmail address e.g.

[email protected]

Can anyone help me with finding an expression that will allow me to do this?

Thanks.