Question

I make this

$("#developments ul").animate({
        marginLeft: -1*((ul_width+li_padding)*(how_many_more+1)+how_many_more*ul_padding)},30000,'linear'
    );

I want to do something when margin-left of ul=-1*((ul_width+li_padding)*(how_many_more)+how_many_more*ul_padding)
Can i use .change() handler? if yes how can i use this handler?
I try this

$("#developments ul").css("margin-left").change(function() {
        alert("handler");
    });

But it doesn’t work..
This is reasonable because $(“#developments ul”).css(“margin-left”) returns a number.
A number as number is static and can’t be change never!!
Any help?

Answer 1

You can tie into the step property of the .animate options

$("#developments ul").animate({
    marginLeft: -1 * ((ul_width + li_padding) * (how_many_more + 1) + how_many_more * ul_padding)
}, {
    duration: 30000,
    easing: "linear",
    step: function(now, fx) {
        if (now === -1 * ((ul_width + li_padding) * (how_many_more) + how_many_more * ul_padding)) {
            alert("handler");
        }
    }
});

Something like that should work.