// JavaScript Validation Functions
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  ALL LETTERS
// If the element's string matches the regular expression it is all letters
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
function isAlphabet(elem, helperMsg){
	var alphaExp = /^[a-zA-Z]+$/;
	if(elem.value.match(alphaExp)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  ALL NUMBERS
// If the element's string matches the regular expression it is all NUMBERS
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// If the element's string matches the regular expression it is all numbers
function isNumeric(elem, helperMsg){
	var numericExpression = /^[0-9]+$/;
	if(elem.value.match(numericExpression)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  NOT EMPTY
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// If the length of the element's string is 0 then display helper message
function notEmpty(elem, helperMsg){
	if(elem.value.length == 0){
		alert(helperMsg);
		elem.focus(); // set the focus to this input
		return false;
	}
	return true;
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  LENGTH RESTRICTION
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
function lengthRestriction(elem, min, max){
	var uInput = elem.value;
	if(uInput.length >= min && uInput.length <= max){
		return true;
	}else{
		alert("Please enter between " +min+ " and " +max+ " characters");
		elem.focus();
		return false;
	}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// CONFIRM SELECTION MADE BY USER
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
function madeSelection(elem, helperMsg){
	if(elem.value == "Please Choose"){
		alert(helperMsg);
		elem.focus();
		return false;
	}else{
		return true;
	}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
/*  E-MAIL VALIDATION FUNCTION
Every email is made up for 5 parts:

   1. A combination of letters, numbers, periods, hyphens, plus signs, and/or underscores
   2. The at symbol @
   3. A combination of letters, numbers, hyphens, and/or periods
   4. A period
   5. The top level domain (com, net, org, us, gov, ...)

Valid Examples:

    * bobby.jo@filltank.net
    * jack+jill@hill.com
    * the-stand@steven.king.com

Invalid Examples:

    * @deleted.net - no characters before the @
    * free!dom@bravehe.art - invalid character !
    * shoes@need_shining.com - underscores are not allowed in the domain name

The regular expression to check for all of this is a little overkill and beyond the scope of this tutorial to explain thoroughly. However, test it out and you'll see that it gets the job done.

*/
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
function emailValidator(elem, helperMsg){
	var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;
	if(elem.value.match(emailExp)){
		return true;
	}else{
		alert(helperMsg);
		elem.focus();
		return false;
	}
}