JavaScript - Test for an integer

Question

I have a text field that allows a user to enter their age. I am trying to do some client-side validation on this field with JavaScript. I have server-side validation already in place. However, I cannot seem to verify that the user enters an actual integer. I am currently trying the following code:

    function IsValidAge(value) {         if (value.length == 0) {             return false;         }          var intValue = parseInt(value);         if (intValue == Number.NaN) {             return false;         }          if (intValue <= 0)         {             return false;         }         return true;     } 

The odd thing is, I have entered individual characters into the textbox like "b" and this method returns true. How do I ensure that the user is only entering an integer?

Thank you

Answer 1

var intRegex = /^\d+$/; if(intRegex.test(someNumber)) {    alert('I am an int');    ... } 

That will absolutely, positively fail if the user enters anything other than an nonnegative integer.