Only be able to press space once every half a sec

Question

When i press spacebar, the function shoot executes.

window.onkeydown=function(e){
    var which = e.keyCode;
    if(which == 32){
        shoot();
    }
}

If you hold space down, shoot calls many times in a row. I only want the function to execute once every 500ms.

Answer 1

(function($){

    var lazerCharging = false,
        lazerChargeTime = 500;  // Charge time in ms

    function handleKeyPress(e){
        if(e.keyCode == 32){
            shoot(lazerChargeTime);   
        }
    }

    function shoot(chargeTime){

        if(!lazerCharging){        

            lazerCharging = true;       
            $("body").append("pew<br/>");

            setTimeout(function(){
                lazerCharging = false;
            }, chargeTime)            
        }        
    }

    $(window).on("keydown", handleKeyPress);

})($);

Here's a jsfiddle