jQuery form with price format
I'm solely going to post on your coding structure rather than the method of procedure for the task your code does.



In validateNumber(), your indentation starts out good and then goes downhill from there.


}else {
var len = $txtBox.val().length;
var index = $txtBox.val().indexOf(',');
if (index &gt; 0 &amp;&amp; event.keyCode == 44) {
return false;
}
if (index &gt; 0) {
var charAfterdot = (len + 1) - index;
if (charAfterdot &gt; 6) {
        return false;
}



with whitespace added would transform into:

} else {
    var len = $txtBox.val().length;
    var index = $txtBox.val().indexOf(',');
    if (index &gt; 0 &amp;&amp; event.keyCode == 44) {
        return false;
    }
    if (index &gt; 0) {
        var charAfterdot = (len + 1) - index;
        if (charAfterdot &gt; 6) {
            return false;
        }




Your naming conventions could be improved also:
For example, charAfterdot into charAfterDot.



Instead of blindly comparing random event.keyCodes with numbers, declare the numbers before hand as constants.  

const BACKSPACE = 8;
const TAB = 9;
const LEFT_ARROW = 37;
const RIGHT_ARROW = 39;


However, your version of JavaScript may not support constants, so use var in that case, and then just:

if (event.keyCode == BACKSPACE || event.keyCode == TAB || event.keyCode == LEFT_ARROW || event.keyCode == RIGHT_ARROW)


Declaring constants is a much clearer way of programming, than comparing to random numbers.