Here’s the process I was looking for:
Check if passed variable is a number
if yes return number+px
if no strip alpha characters from beginning or end of number
return number+px

I am just wondering why you need this function at all. As you can see by declaring “var” before a variable in javascript it does not really care if a string or integer is held in it unless you are doing validation or variable specific tasks.

So .. First of all, you create your variable “oldValue” (which could be anything at all as input to your function) that should be an integer number to represent a pixel value in HTML – by adding “px”.

Why not simply state;

var oldvalue = ’65′; (this has been created as a string – but javascript does not care)
var newValue = oldValue + “px”; (newValue is now equal to “65px”)

document.write(newValue);

Another thing is that by using the parseInt function (this function is used to parse an integer and return a string), in essence you are passing a string into a function that converts this to an integer, parses it and once again returns a string. This function is better suited to parsing strings that might contain both an integer and a string “tail” or in converting different numerical systems such as decimal to octal. You can see an example here : http://www.w3schools.com/jsref/jsref_parseInt.asp

The only purpose I could see in using this would be for validation but then there is nothing done inside the function px() to handle any errors.

Its amazing how such a small piece of code can cause such a discussion, please let me know what it is that I may have missed.

Darren