How to trap double key press in javascript?

Question

I would like to be able to trap the double key press (for the Char T for example) in order to do some special processing.I would like the key presses to happen fast enough t

Answer 1

When the key(s) are hit, make a note of the time. Then compare it with the time you noted the last time they key(s) were hit.

If the difference is within your threshold, consider it a double. Otherwise, don't. Rough example:

var delta = 500;
var lastKeypressTime = 0;
function KeyHandler(event)
{
   if ( String.fromCharCode(event.charCode).toUpperCase()) == 'T' )
   {
      var thisKeypressTime = new Date();
      if ( thisKeypressTime - lastKeypressTime <= delta )
      {
        doDoubleKeypress();
        // optional - if we'd rather not detect a triple-press
        // as a second double-press, reset the timestamp
        thisKeypressTime = 0;
      }
      lastKeypressTime = thisKeypressTime;
   }
}