JavaScript Forum

**The_Anomaly** · 06-13-2005, 07:25 PM

whats crackin, new on the forums have a quick question. i need to make a text box that will validate an integer without using the isNaN function. anyone have any idea's? o yeah, i cant use the NaN because its a homework assignment, i'm not trying to get everyone to do my homework, this one's just splitting me head open.

**Phaedrus** · 06-13-2005, 08:21 PM

Try performing a mathematical calculation on it and testing the answer. Something like:

Code:

<html>
<head>
<script>
function numCheck(x)
{
	myInt = x.value;
	if ( ((myInt + 1)>=0) || ((myInt + 1)<0) )
	{
	    alert("it's valid");
	}
	else
	{
	    alert("it's invalid");
	}	
}
</script>
</head>
<body>

<input type="text" name="num" onBlur="numCheck(this);" />

</body>
</html>

**The_Anomaly** · 06-13-2005, 08:49 PM

Seems to work well, only thing i was a little worried about was it didnt do anything when the box was empty. works for me though.

i tried doing a mathmatical operation on my variable to make it work like this before but i must have been doing something wrong. thx Phaedrus