text box validation

[lolodede]

hi
thank you very much for replying quickly if i could do anything tell me
im new to javascript so i have problem with validating text box to accept only positive numbers and not more than 1000

thanks

[acoder]

You could use a regular expression:

/^\d+$/

to test that there are only integers. Once you have that established, use parseInt to convert the string into an integer and test that it's less than 1000:

if (parseInt(str) > 1000) {
   alert("Error ...");
}

[lolodede]

sorry but i dont know regular expression and i try everything didnt work

[acoder]

See this and this to get acquainted. If you don't want to use a regular expression, you could create isDigit()/isInteger()/isPositiveInteger() functions, e.g.

function isDigit(num) {
    if (num.length > 1) return false;
    var str="1234567890";
    return (str.indexOf(num) != -1);
}

[lolodede]

its not working i dont why can use isnan function if yes how

[acoder]

isNaN wouldn't be enough. The code I posted for isDigit should be used to test one character. Test all characters to test if the string is a positive integer, e.g.

function isInteger(num) {
    for (i = 0; i < num.length; i++) {
        var char = num.charAt(i);
        if (!isDigit(char)) return false;
    }
    return true;
}

[lolodede]

this is the script i have but i want to add the intger shouldnt be more than 100 ie between 0-100

<script type="text/javascript">
<!--
function checkNum(number)
{
if (isNaN(number.value) )
  {
    alert(number.value + " is not a number. Please re-enter.");
    number.focus();
    number.select();
  }
  return;
}

[lolodede]

i have this code but i want to put more than 1000 is not accepted

function checkNum(number)
{ 
if (isNaN(number.value) )
  {
    alert(number.value + " is not a number. Please re-enter.");
    number.focus();
    number.select();
  }
 
  return;
}

[acoder]

isNaN will be false for float numbers too, e.g. 1.23, but you only want positive integers.

Anyway, to check if the number is not greater than 1000, see post #2.