Here's a nice little addon to the Prototype Ajax library that adds the ability to trim text, etc. with Prototype.

First add this to one of your .js include files,

String.prototype.trim = function() {
    return this.replace(/^\s+|\s+$/g,"");
}
String.prototype.ltrim = function() {
    return this.replace(/^\s+/,"");
}
String.prototype.rtrim = function() {
    return this.replace(/\s+$/,"");
}

now with protoype loaded you can trim your text simply and effectivly,

$('myfield').value.trim() == '';

this will simply get the value from the textbox 'myfield', trim it for whitespace and then compare it to see if it's empty.

Sweet!

Thanks goes to SOMACON.COM for this one.