isPalindrome

Checks if its a Palindrome purely mathematically special thanks to Mike Potter for the more elegant solution.

by Christopher Stephens

HTML

This is to demonstrate a isPalindrome algorithm using just a Number.
<div id="console"></div>

JavaScript

console.log = function (msg) {
    $("#console").append("<div>" + msg + "</div>");
};

var myNumber = prompt("Palindrome checker", "Please enter a number");

function isPalindrome(toTest) {
    if (toTest < 10) {
        return true;
    }

    var frontNumber;
    var lastNumber;
    var div = 1;
    
    // find out where to start
    while (toTest / div >= 10) {
        div = div * 10; 
    }
    
    while (toTest != 0) {
        frontNumber = parseInt(toTest / div); 
        lastNumber = parseInt(toTest % 10);

        if (frontNumber != lastNumber) {
             return false; 
        }
        toTest = parseInt((toTest % div) / 10);
        div = div / 100;
    }
    
    return true;
} 

console.log(myNumber + (isPalindrome(myNumber) ? " is " : " is not ") + "a Palindrome");