mousedown时的JavaScript [英] JavaScript while mousedown

问题描述

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;
}

我想在鼠标停机时运行代码，我找不到任何暗示我可以做的事情（mousedown）所以我试图为mousedown制作一个标志，它在鼠标上重置然而我相信while循环是什么导致我陷入无限循环。

I'm wanting to run code while the mouse is down, i cant find anything to suggest i can do while(mousedown) so i've tryed making a flag for mousedown which is reset on mouse up however i beleive the while loop is whats causing me to go get stuck in an infinite loop.

任何有关我正在努力实现的建议？

Any advice to help with what i'm trying to acheive?

推荐答案

你有在某个合理的时间间隔内调用mousedown活动。我这样做：

You have to invoke the mousedown activity in some reasonable interval. I'd do this:

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);

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