function validate(aInput, type) 
{
	var regExp = "";
	var strToMatch = aInput.value.toLowerCase();
	
	switch (type){
		case "username":
			regExp = /^[\a-z\ \']+$/;
			break;
		case "email":
			regExp = /^([\w_\.\-])+\@(([\w\-]{2,})+\.)+([\w]{2,})$/;
			break;
		case "password":
			regExp =/^[\w\-\_\.\/\:]+$/;
			break;
		default:
			return true;
	}
	  
	if (strToMatch.match(regExp) || aInput.value == "")
      	return true;
	else
		return false;
}