jQuery/Javascript calculator that auto-updates realtime (guessing AJAX)
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I'm looking to create a pretty simple calculator, but I need it to update on each keystroke. I  cannot seem to find anything in that specific category. Can anyone point me to the right direction? 

I'm looking for something like A*1.325 + B*3.76 where B is a drop down menu and A is the text field that people will be filling out. Every time the drop down is changed or a keystroke is registered in the text box.

I will also try to do some RegEx to only allow numbers or decimal points!

Thank you guys very much!!!

PS. Will be using PHP/HTML to create the form.
