IE8中的参数的setTimeOut不起作用

Question

Can some one tell me where I am going wrong here, I have tested it in Firefox and Chrome and it works okay just need it working in IE8 now.

        setTimeout(function(it) {
            x = $('.menuheader:first-child').position().left;
            w = $('.menuheader:first-child').width();
            p = x + w + 16;
            $(it).next().css('left', p);
            $(it).next().show();
        }, 200, this);

Also tried...

        function showmenu(it){
            x = $('.menuheader:first-child').position().left;
            w = $('.menuheader:first-child').width();
            p = x + w + 16;
            $(it).next().css('left', p);
            $(it).next().show();
        }

        window.setTimeout(function() {
            showmenu(this)
        }, 200);

Answer 1

The correct legacy way to "pass parameters" to a function that can't accept them is with a closure:

var that = this;
setTimeout(function(){ doStuff(that);}, 200);

function doStuff(it) {
   x = $('.menuheader:first-child').position().left;
   w = $('.menuheader:first-child').width();
   p = x + w + 16;
   $(it).next().css('left', p);
   $(it).next().show();
}

A newer alternative (not compatible with IE8 without a polyfill):

 setTimeout(doStuff.bind(null, this), 200);

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Answer 2

I've never found setTimeout parameters to be particularly reliable, so I just do this:

var it = this;
setTimeout(function() { ... }, 200);