Need javascript code for button press and hold

When the button is pressed, call window.setTimeout with your intended time and the function x, and set the timer again at the end of x but this time with a smaller interval.

Clear the timeout using window.clearTimeout upon release of the mouse button.

function holdit(btn, action, start, speedup) {
    var t;

    var repeat = function () {
        action();
        t = setTimeout(repeat, start);
        start = start / speedup;
    }

    btn.mousedown = function() {
        repeat();
    }

    btn.mouseup = function () {
        clearTimeout(t);
    }
};

/* to use */
holdit(btn, function () { }, 1000, 2); /* x..1000ms..x..500ms..x..250ms..x */

Just put the below toggleOn in the OnMouseDown and toggleOff in the OnMouseUp of the button.

var tid = 0;
var speed = 100;

function toggleOn(){
    if(tid==0){
        tid=setInterval('ThingToDo()',speed);
    }
}
function toggleOff(){
    if(tid!=0){
        clearInterval(tid);
        tid=0;
    }
}
function ThingToDo{

}