Chapter 7: Form Handling

Validating Email Addresses

Script 7.15

This JavaScript scans through the text within an e-mail field on your form, and ensures that you get properly formed e-mail addresses.

window.onload = initForms;

function initForms() {
	for (var i=0; i< document.forms.length; i++) {
		document.forms[i].onsubmit = function() {return validForm();}
	}
	document.getElementById("sunroof").onclick = doorSet;
}

function validForm() {
	var allGood = true;
	var allTags = document.getElementsByTagName("*");

for (var i=0; i<allTags.length; i++) {
		if (!validTag(allTags[i])) {
			allGood = false;
		}
	}
	return allGood;

for (var k=0; k<document.forms.length; k++) {
				if (!radioSet) {
					radioSet = document.forms[k][radioName];
				}
			}
			if (!radioSet) return false;
			for (k=0; k<radioSet.length; k++) {
				if (radioSet[k].checked) {
					return true;
				}
			}
			return false;
		}
		
		function isNum(passedVal) {
			if (passedVal == "") {
				return false;
			}
			for (var k=0; k<passedVal.length; k++) {
				if (passedVal.charAt(k) < "0") {
					return false;
				}
				if (passedVal.charAt(k) > "9") {
					return false;
				}
			}
			return true;
		}
		
		function isZip(inZip) {
			if (inZip == "") {
				return true;
			}
			return (isNum(inZip));
		}
		
		function validEmail(email) {
			var invalidChars = " /:,;";
		
			if (email == "") {
				return false;
			}
			for (var k=0; k<invalidChars.length; k++) {
				var badChar = invalidChars.charAt(k);
				if (email.indexOf(badChar) > -1) {
					return false;
				}
			}
			var atPos = email.indexOf("@",1);
			if (atPos == -1) {
				return false;
			}
			if (email.indexOf("@",atPos+1) != -1) {
				return false;
			}
			var periodPos = email.indexOf(".",atPos);
			if (periodPos == -1) {	
				return false;
			}
			if (periodPos+3 > email.length)	{
				return false;
			}
			return true;
		}
		
		function invalidLabel(parentTag) {
			if (parentTag.nodeName == "LABEL") {
				parentTag.className += " invalid";
			}
		}
	}
}

function doorSet() {
	if (this.checked) {
		document.getElementById("twoDoor").checked = true;
	}
}

Contents:

Validating Email Addresses

Script 7.15