javascript, detect seconds between keypress

detection.js

milliseconds = 0;
timeHandle = null;
window.onkeypress = function(){
    clearInterval(timeHandle);
    if (milliseconds > 0){
        console.log('passed ' + milliseconds*10 + ' milliseconds');
        milliseconds = 0;
    }
    timeHandle = setInterval(function(){
    milliseconds++;
  },10);
}