Question

var h=0;
var w=0;
    $(".extend").hover(function() {

        //alert(h);
        $(this).css({'z-index' : '999' });
        $(this).addClass("hover").filter(":not(:animated)").stop()
            .animate({
                marginTop: '-110px', 
                marginLeft: '10px', 
                top: '80%', 
                left: '80%',
                width: 387, 
                height: 487,
                padding: '0px' 
            }, 200);
         h=$(this).height();
         w=$(this).width();
        } , function() {
        $(this).css({'z-index' : '0'});
        $(this).removeClass("hover").stop()
            .animate({
                marginTop: '0', 
                marginLeft: '0',
                top: '0', 
                left: '0', 
                width:w,
                height:h,
                padding: '0px'
            }, 400);
    });

<img class="extend" src="a.jpg">
<img class="extend" src="b.jpg">

I have problem with my hover function i can’t make the image back to original size if i hover it to a.jpg it expand then i hover over to b.jpg without waiting a.jpg to return to original size it will become bigger and bigger.

How i can hover and expand without shifting the size?

Answer 1

Unless you need your width and height to change, you should only set it once, assuming both images are the same size this should work

var h=$(".extend").height();
var w=$(".extend").width();
    $(".extend").hover(function() {

        //alert(h);
        $(this).css({'z-index' : '999' });
        $(this).addClass("hover").filter(":not(:animated)").stop()
            .animate({
                marginTop: '-110px', 
                marginLeft: '10px', 
                top: '80%', 
                left: '80%',
                width: 387, 
                height: 487,
                padding: '0px' 
            }, 200);
        } , function() {
        $(this).css({'z-index' : '0'});
        $(this).removeClass("hover").stop()
            .animate({
                marginTop: '0', 
                marginLeft: '0',
                top: '0', 
                left: '0', 
                width:w,
                height:h,
                padding: '0px'
            }, 400);
    });

FIDDLE

EDIT–
For images with different dimensions save them in the element using .data()

$(".extend").each(function(){
    $(this).data('width', $(this).width());
    $(this).data('height', $(this).height());
})
$(".extend").hover(function() {

    //alert(h);
    $(this).css({'z-index' : '999' });
    $(this).addClass("hover").filter(":not(:animated)").stop()
        .animate({
            marginTop: '-110px', 
            marginLeft: '10px', 
            top: '80%', 
            left: '80%',
            width: 387, 
            height: 487,
            padding: '0px' 
        }, 200);
    } , function() {
    $(this).css({'z-index' : '0'});
    $(this).removeClass("hover").stop()
        .animate({
            marginTop: '0', 
            marginLeft: '0',
            top: '0', 
            left: '0', 
            width:$(this).data('width'),
            height:$(this).data('height'),
            padding: '0px'
        }, 400);
});

FIDDLE

EDIT-2-
A simple way to solve the shifting problem is to wrap the img tags in an inline-block element, set the elements dimensions to that of the image then make the img absolutly positioned

<span><img class="extend" src="a.jpg"></span>
<span><img class="extend" src="b.jpg"></span>​

$(".extend").each(function(){
    $(this).data('width', $(this).width());
    $(this).data('height', $(this).height());
    $(this).parent().css({display:'inline-block', width: $(this).width(), height: $(this).height()})
    .end().css({position:'absolute'});
})
$(".extend").hover(function() {

    //alert(h);
    $(this).css({'z-index' : '999' });
    $(this).addClass("hover").filter(":not(:animated)").stop()
        .animate({
            marginTop: '-110px', 
            marginLeft: '10px', 
            top: '80%', 
            left: '80%',
            width: 387, 
            height: 487,
            padding: '0px' 
        }, 200);
    } , function() {
    $(this).css({'z-index' : '0'});
    $(this).removeClass("hover").stop()
        .animate({
            marginTop: '0', 
            marginLeft: '0',
            top: '0', 
            left: '0', 
            width:$(this).data('width'),
            height:$(this).data('height'),
            padding: '0px'
        }, 400);
});

FIDDLE