regex phone number validation with PHP

Question

This is another question about a previous question I had asked yesterday. I want user to be allowed to type US phone numbers in the following formats.

(800)-555-121

Answer 1

if javascript is ok can go with

call this function onsubmit of form or onblur of textbox

If you have doubt about your regex you can validate it at http://www.regular-expressions.info/javascriptexample.html