setTimeout函数没有调用？

Question

To put a delay on a menu onmouseover effect, setTimeout is one of the options. But when I try it, the function isn't called.

HTML:

  <li><a href="#"  
         onmouseover="mopendelay('menu_proj')" 
  <li>

JavaScript:

// open hidden layer
function mopen(id)
{   
    // cancel close timer
    mcancelclosetime();

    // close old layer
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

    // get new layer and show it
    ddmenuitem = document.getElementById(id);
    ddmenuitem.style.visibility = 'visible';

}

// delay menu open on mouseover
function mopendelay(id) 
{
    var delay = setTimeout(function(){
      alert('delay'); // isn't called
      mopen(id);
    }, 200);
    clearTimeout(delay);
}

Answer 1

You're clearing timeout before the timeout function can execute.

function mopendelay(id) 
{
    var delay = setTimeout(function(){
        mopen(id);
    }, 200);
}

Answer 2

You're immediately calling clearTimeout on the handle returned by setTimeout . Why is that? I believe the code will work as expected if you remove that.

Answer 3

You're calling clearTimeout directly afterward. Whatever for? Remove that line, and it will work correctly.

Answer 4

您的清除超时应该在传递给setTimeout的函数之外