The Math Forum: 1998 Summer Institute - sum98

Javascript: Form Validation

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1998 Summer Institute || Participant Projects || List of Participants || Sum98 Staff || Agenda
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The Javascript functions below are common form validation techniques. Take a look. Copy and paste these functions into your own pages as you need them. The previous page shows how they get called in the HTML document.



<SCRIPT LANGUAGE="javascript">

 function noEntry(){
  input_value=document.forum.largetext.value;
  if (input_value.length<1){
   
	alert("Please complete the required form field below.");

	document.forum.largetext.focus();
  }
}




function emailCheck() {
	myvalue = document.forum.text1.value;

	if ((myvalue.indexOf("@") >= 0) && (myvalue.indexOf(" ") < 0)) {
		return true;
	} else { 
		alert("Please enter a valid email address.");
		return false;
	}	
}



function makeChoice() {
	thevalue = document.forum.list1.selectedIndex;
	
	if (thevalue == 0) {
		alert("Please make a choice from the list");
		return false;
	} else {
		return true;
	}
}



function checkChecker() {
	my_value = document.forum.drink.checked;
	your_value = document.forum.live.checked;
	if ((my_value == "0") && (your_value =="0")) {
		alert("Milk does a body good!"
		+"\r\r\r\r\r"+" -Sponsored by the National Dairy Council");
		document.forum.drink.checked = "1";	
	}
	
}

</SCRIPT>

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Math Forum

7 July 1998