Regular Expressions

[Doreen22]

I have seen regular expressions declared a few different ways, in Javascript. Which is best?1) var regex = new RegExp(/^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/);2) var regex=/^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/ ;3) same as 2, but without the semicolon at the end (my program chokes on that one, but I've seen it on several sites). I am using Javascript in XHTML code (not sure if that makes a difference). Thanks!Doreen

[jeffman]

XHTML won't make a difference.1 and 2 both create a regex object. I have the impression that most experienced developers use 2. The use of a semicolon at the end of a statement is optional, but most experienced developers do it.

[ShadowMage]

I think the main difference is that you can pass a string in the first technique which then enables the usage of variables to create regexes.

[jeffman]

Yes. I forget about that sometimes, but I have used it that way.