Question

I am working on a nested menu, and when my mouse move over a option, a sublist will show up.
Here is my hover function:

$( ".sublist" ).parent().hover( function () {
    $(this).toggleClass("li_hover",300); //use to change the background color
    $(this).find(".sublist").toggle("slide", {}, 500); //sub list show / hide
});

Now, I want add a short period before the sublist shows up to prevent the crazy mouse moving from user. Does somebody have a good suggestion on this?

---

Update:

Thanks for you guys, I did a little bit change on my program, recently it looks like this:

function doSomething_hover (ele) {
    ele.toggleClass("li_hover",300);
    ele.find(".sublist").toggle("slide", {}, 500);
}

$(function () {
    $( ".sublist" ).parent().hover( function () {
        setTimeout(doSomething_hover($(this)), 3000);
    });
}):

This is weird that setTimeout will not delay anything. but if I change the function call to doSomething_hover (without “()”), the function will delay good. but i can not pass any jquery element to the function, so it still not works, could somebody tell me that how to make doSomething_hover($(this)) work in setTimeout ?

---

Update 2:
Got the setTimeout work, but it seems not what I want:
What I exactly want is nothing will happen, if the mouse hover on a option less than 0.5sec.

Anyway, here is the code I make setTimeout work:

function doSomething_hover (ele) {
    ele.toggleClass("li_hover",300);
    ele.find(".sublist").toggle("slide", {}, 500);
}

$(function () {
    $( ".sublist" ).parent().hover( function () {
        var e = $(this);
        setTimeout(function () { doSomething_hover(e); }, 1000);
    });
}):

---

Final Update:
I got this work by using clearTimeout when I move the mouse out.
so the code should be:

    $( ".sublist" ).parent().mouseover( function () {
        var e = $(this);
        this.timer = setTimeout(function () { doSomething_hover(e); }, 500);
    });

    $( ".sublist" ).parent().mouseout ( function () {
        if(this.timer){
            clearTimeout(this.timer);
        }
        if($(this).hasClass("li_hover")){
            $(this).toggleClass("li_hover");
        }
        $(this).find(".sublist").hide("slide", {}, 500);

    });

This is the part in the $(document).ready(). Other code will be same as above.

---

真. Final Update:
So, mouseover and mouseout will lead to a bug sometime, since when I move the mouse to the sublist, the parents’ mouseover event will be fire, and hide the sublist.
Problem could be solved by using hover function:

    $( ".sublist" ).parent().hover( 
        function () {
            var e = $(this);
            this.timer = setTimeout(function () { doSomething_hover(e); }, 500);
        },
        function () {
            if(this.timer){
                clearTimeout(this.timer);
            }
            $(this).find(".sublist").hide("slide", {}, 500);
            if($(this).hasClass("li_hover")){
                $(this).toggleClass("li_hover",300);
            }
        }
    );

Thanks all

Answer 1

Try this please:

Code

setInterval(doSomthing_hover, 1000);


function doSomthing_hover() {
    $(".sublist").parent().hover(function() {

        $(this).toggleClass("li_hover", 300); //use to change the background color
        $(this).find(".sublist").toggle("slide", {}, 500); //sub list show / hide
    });

}​

SetTime vs setInterval

At a fundamental level it’s important to understand how JavaScript timers work. Often times they behave unintuitively because of the single thread which they are in. Let’s start by examining the three functions to which we have access that can construct and manipulate timers.

var id = setTimeout(fn, delay); – Initiates a single timer which will call the specified function after the delay. The function returns a unique ID with which the timer can be canceled at a later time.

var id = setInterval(fn, delay); – Similar to setTimeout but continually calls the function (with a delay every time) until it is canceled.

clearInterval(id);, clearTimeout(id); – Accepts a timer ID (returned by either of the aforementioned functions) and stops the timer callback from occurring.

In order to understand how the timers work internally there’s one important concept that needs to be explored: timer delay is not guaranteed. Since all JavaScript in a browser executes on a single thread asynchronous events (such as mouse clicks and timers) are only run when there’s been an opening in the execution.

Further read this: http://ejohn.org/blog/how-javascript-timers-work/