form validation

[irate]

can anyone show me a quick script that will check a text box to make sure it only contains numbers?

ie.

<form action=&quot;executescript.asp&quot; method=&quot;post&quot;>
<input type=&quot;text&quot; name=&quot;cost&quot;>
</form>

make sure the text box only contains the characters 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

 

[bvallet]

Try this:

function checkNumber(NumberField){
	var pattern =/\D/;
	var text = NumberField.value;
	var result = text.match(pattern);
	if(NumberField.value==""){
		NumberField.value = 0;
		return true;	
	}
	else{ 
		if((result != null)){
			alert("You must enter a number in this field.\nPlease do not enter letters or decimal points");
			NumberField.focus();
			NumberField.select();
			return false;
		}
		else{
			return true;
		}
	}
}
[code]

This works well for integers and could easily be adapted for decimals. I call it like this:
[code]
<INPUT NAME=&quot;Number&quot; VALUE=&quot;&quot; onChange=&quot;
	if(!checkNumber(this))
		return false;
&quot;>

 

[Damian13]

These functions do it, not so simple but its ok

function isInteger (s)

{ var i;

if (isEmpty(s))
// Search through string's characters one by one
// until we find a non-numeric character.
// When we do, return false; if we don't, return true.

for (i = 0; i < s.length; i++)
{
// Check that current character is number.
var c = s.charAt(i);

if (!isDigit(c)) return false;
}

// All characters are numbers.
return true;

}

function isDigit (c)
{ return ((c >= &quot;0&quot && (c <= &quot;9&quot)
}

 

[irate]

I found this code on the netscape website

floatValue=parseFloat(toFloat)
if (isNaN(floatValue))
{ notFloat()}
else
{ isFloat()}





did you not know this or is there a reason why you wouldnt use this or it is bad?

 

[bvallet]

I came up with that function when I first started working with Javascript and didn't know anything (as if I know anything now). It's worked for me so I never bothered to look for anything else.

The one you found looks like it would work fine.