It simply replaces the double or single quotation mark character that you just typed with a pair of them and then moves the cursor in between the pair so you are ready to type the attribute's value. This mapping can get annoying if you find yourself typing quote characters for reasons other than attributes, and you don't want the matching end-quote--you could make it better using a function along the lines of VimTip102 to maybe only do it when the prior charater is an equal sign '=' , but I ended up liking it this simple way.