How do I use regex to perform a validation?

I'd like to evaluate a form field using a regex.

What expression do I use to actually compare t开发者_如何学Pythonhe value to the regex?

I'm imagining something thus:

if($('#someID').val() == /someregex/) {doSomething()}

But that doesn't work. Any advice?

---

Use

if (/^someregex$/.test($('someID').value()) {
     // match
} else {
     // no match
}

---

Note that there is no value() method in jQuery, you need to use val() and match like this:

if($('#someID').val().match(/someregex/) {
  // success
}

More Info:

• http://www.regular-expressions.info/javascript.html

---

use the match method of the strings..

string.match(regexp)

so in your case

if( $('#someID').value().match(/someregex/) ) {doSomething()}

---

I think you're looking for .test():

var myRegex = /someregex/;
if ( myRegex.test($('#someID').value()) ) {
    doSomething();
}

You can use exec() to check it and get an array of it's matches, or match() from the string object.

---

We don't compare values to regular expressions. We use regular expressions to test if a value matches a pattern.

---

Something like:

if (/myRegExp/.test($('#myID').val()) { 
  //... do whatever 
}

see http://www.evolt.org/regexp_in_javascript