Validation for numeric value-JavaScript

function IsNumeric(strString)
// check for valid numeric strings
{
var strValidChars = "0123456789.-";
var strChar;
var blnResult = true;

if (strString.length == 0) return false;

// test strString consists of valid characters listed above
for (i = 0; i < strString.length && blnResult == true; i++)
{
strChar = strString.charAt(i);
if (strValidChars.indexOf(strChar) == -1)
{
blnResult = false;
}
}
return blnResult;
}
**********************************
function NumbersOnly(e)
{
var unicode=e.charCode? e.charCode : e.keyCode
if (unicode<48||unicode>57)
return false

}
***************************************
U can use the below javascript:

function valInteger(obj)
{
var i,strVal,blnChange;
blnChange = false
strVal="";

for(i=0;i<(obj.value).length;i++)
{
switch(obj.value.charAt(i))
{
case "0":
case "1":
case "2":
case "3":
case "4":
case "5":
case "6":
case "7":
case "8":
case "9":strVal=strVal+obj.value.charAt(i);
break;
default :blnChange = true;
break;
}
}
if (blnChange)
{
obj.value=strVal;
}
}

Page ,for that textbox'a keyup give like this

onkeyup="return valInteger(this)"