There are some handy functions in PHP you would sometimes like to have in JavaScript, too. Why not reimplement them? It’s not hard. Take for example in_array() and explode():

function explode(delim, val_to_split)
{
	return (val_to_split.indexOf(delim))
		? val_to_split.split(delim)
		: [val_to_split];
}
 
function in_array(needle, haystack)
{
	hlength = haystack.length;
	for (var i=0; i<length; i++)
		{ if (needle == haystack[i])
			{ return true; } }
	return false;
}

Hint: On many pages of PHP functions, there are comments which describe how to reimplement a function (e.g. PHP 4 implementations of PHP 5 functions) — in PHP though, but it’s easy to adapt them for JavaScript.