How can I create alike css classes

[KristenL]

I want to create css classes depending upon what user has specified a width in a textfield. I know I can do it using inline styles, but I want to avoid it as there are many properties to be taken care of. In this question "width" is just an example.For eg: if user specifies width as "20" then I want -\[code\].w20 {width:20px}\[/code\]if user specifies 21 then I want\[code\].w21 {width:21px}\[/code\]and so on...FIDDLEThanks.