function getCaller(e) {
	var t;
	if (!e) {
	  var e = window.event;
	}
	
	if (e.target) {
	  t = e.target;
	} else if (e.srcElement) {
	  t = e.srcElement;
	}
	
	if (t.nodeType == 3) { /* Safari-compatible */
	 t = t.parentNode;
	}
	return t;
}


function guestLimit(e) {

	var guestLimit = 7;
	var guestLimitRegex = new RegExp("^[0-9]{1}", "g");
	 
	var event = document.getElementById(getCaller(e).id);
	var regexTest = guestLimitRegex.test(event.value);
	
	if(!regexTest && event.value != '') {
		alert("Guest limit must be a number");
		event.value = 0;
		event.select();
	} else if(event.value > guestLimit) {
		alert("Guest limit per event is " + guestLimit);
		event.value = 7;
		event.select();
	}
}

function guestLimitMin(e) {
	 
	var event = document.getElementById(getCaller(e).id);
	
	if(event.value == '') {
		event.value = 0;
	}
}