jQuery / Javascript - How do I convert a pixel value (20px) to a number value (20)

No jQuery required for this, Plain Ol' JS (tm) will do ya,

parseInt(a, 10);

More generally, parseFloat will process floating-point numbers correctly, whereas parseInt may silently lose significant digits:

parseFloat('20.954544px')
> 20.954544
parseInt('20.954544px')
> 20

 var c = parseInt(a,10);

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