eregi() deprecated - I am not sure how to rewrite this code

eregi() deprecated - I am not sure how to rewrite this code

Deprecated code:
function validate_email($email) { return
eregi("^[_.0-9a-zA-Z-]+@([0-9a-zA-Z][0-9a-zA-Z-]+.)+[a-zA-Z]{2,6}$",
$email); }
I am a JavaScript beginner. The above code gives an error. I am not too
sure how to rewrite using preg_match.