In my web development work, I’m quite fond of using the trick of generating grouped elements by making sure their IDs all share a common number with a bit of unique text.
So for example I could have a set of elements with the IDs accordionheading1, accordionpanel1, accordiontext1 and accordionheading2, accordionpanel2, accordiontext2. Now in order for this to be useful, I need to be able to extract the number from these strings so that I can automatically guess an element’s associated partners, meaning that you now know exactly what is coming next:
One of the easier ways of extracting a number from a string using javascript is by making use of a bit of regex, utilizing the digit negated shorthand character class \D to do our dirty work.
In practice:
var element = 'accordion24paneldrop'; id = element.replace( /\D+/g, ''); alert(id); //24
Nifty.
Check it else for yourself using JSFiddle! (JS Bin is pretty cool too)