鼠标按下时的 JavaScript

Question

var mdflag;
var count = 0;

document.addEventListener("mousedown",mdown,false);
    document.addEventListener("mouseup",mup,false);
}


function mdown()
{
    mdflag=true;
    while(mdflag)
    document.getElementById("testdiv").innerHTML = count++;

}
function mup()
{
    mdflag = false;
}

我想在鼠标按下时运行代码，我找不到任何建议我可以做 while(mousedown) 所以我尝试为 mousedown 制作一个标志，它在鼠标按下时重置但是我相信 while循环是什么导致我陷入无限循环。

有什么建议可以帮助我实现目标吗？

Answer 1

您必须在某个合理的时间间隔内调用 mousedown 事件。我会这样做:

var mousedownID = -1;  //Global ID of mouse down interval
function mousedown(event) {
  if(mousedownID==-1)  //Prevent multimple loops!
     mousedownID = setInterval(whilemousedown, 100 /*execute every 100ms*/);


}
function mouseup(event) {
   if(mousedownID!=-1) {  //Only stop if exists
     clearInterval(mousedownID);
     mousedownID=-1;
   }

}
function whilemousedown() {
   /*here put your code*/
}
//Assign events
document.addEventListener("mousedown", mousedown);
document.addEventListener("mouseup", mouseup);
//Also clear the interval when user leaves the window with mouse
document.addEventListener("mouseout", mouseup);