Wednesday, May 30, 2012

jQuery: How to position one element relative to another?


I have a hidden DIV which contains a toolbar-like menu.



I have a number of DIVs which are enabled to show the menu DIV when the mouse hovers over them.



Is there a built-in function which will move the menu DIV to the top right of the active (mouse hover) DIV? I'm looking for something like $(menu).position("topright", targetEl);


Source: Tips4all
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7 comments:

  1. UserMay 30, 2012 at 3:53 AM

    tl;dr: (try it here)

    If you have the following HTML:

    <div id="menu" style="display: none;">
    <!-- menu stuff in here -->
    <ul><li>Menu item</li></ul>
    </div>

    <div class="parent">Hover over me to show the menu here</div>


    then you can use the following JavaScript code:

    $(".parent").mouseover(function() {
    // .position() uses position relative to the offset parent,
    var pos = $(this).position();

    // .outerWidth() takes into account border and padding.
    var width = $(this).outerWidth();

    //show the menu directly over the placeholder
    $("#menu").css({
    position: "absolute",
    top: pos.top + "px",
    left: (pos.left + width) + "px"
    }).show();
    });


    But it doesn't work!

    This will work as long as the menu and the placeholder have the same offset parent. If they don't, and you don't have nested CSS rules that care where in the DOM the #menu element is, use:

    $(this).append($("#menu"));


    just before the line that positions the #menu element.

    But it still doesn't work!

    You might have some weird layout that doesn't work with this approach. In that case, just use jQuery.ui's position plugin (as mentioned in an answer below), which handles every conceivable eventuality. Note that you'll have to show() the menu element before calling position({...}); the plugin can't position hidden elements.

    Update notes 3 years later in 2012:

    (The original solution is archived here for posterity)

    So, it turns out that the original method I had here was far from ideal. In particular, it would fail if:


    the menu's offset parent is not the placeholder's offset parent
    the placeholder has a border/padding


    Luckily, jQuery introduced methods (position() and outerWidth()) way back in 1.2.6 that make finding the right values in the latter case here a lot easier. For the former case, appending the menu element to the placeholder works (but will break CSS rules based on nesting).

    ReplyDelete
  2. UserMay 30, 2012 at 3:53 AM

    You can now use

    $("#my_div").position({
    my: "left top",
    at: "left bottom",
    of: this, // or $("#otherdiv)
    collision: "fit"
    })


    for fast positionning (UI/API/1.8/Position).

    ReplyDelete
  3. UserMay 30, 2012 at 3:53 AM

    This is what worked for me in the end.

    var showMenu = function(el, menu) {
    //get the position of the placeholder element
    var pos = $(el).offset();
    var eWidth = $(el).outerWidth();
    var mWidth = $(menu).outerWidth();
    var left = (pos.left + eWidth - mWidth) + "px";
    var top = 3+pos.top + "px";
    //show the menu directly over the placeholder
    $(menu).css( {
    position: 'absolute',
    zIndex: 5000,
    left: left,
    top: top
    } );

    $(menu).hide().fadeIn();
    };

    ReplyDelete
  4. UserMay 30, 2012 at 3:54 AM

    Here is a jQuery function I wrote that helps me position elements.

    Here is an example usage:

    $(document).ready(function() {
    $('#el1').position('#el2', {
    anchor: ['br', 'tr'],
    offset: [-5, 5]
    });
    });


    The code above aligns the bottom-right of #el1 with the top-right of #el2. ['cc', 'cc'] would center #el1 in #el2. Make sure that #el1 has the css of position: absolute and z-index: 10000 (or some really large number) to keep it on top.

    The offset option allows you to nudge the coordinates by a specified number of pixels.

    The source code is below:

    jQuery.fn.getBox = function() {
    return {
    left: $(this).offset().left,
    top: $(this).offset().top,
    width: $(this).outerWidth(),
    height: $(this).outerHeight()
    };
    }

    jQuery.fn.position = function(target, options) {
    var anchorOffsets = {t: 0, l: 0, c: 0.5, b: 1, r: 1};
    var defaults = {
    anchor: ['tl', 'tl'],
    animate: false,
    offset: [0, 0]
    };
    options = $.extend(defaults, options);

    var targetBox = $(target).getBox();
    var sourceBox = $(this).getBox();

    //origin is at the top-left of the target element
    var left = targetBox.left;
    var top = targetBox.top;

    //alignment with respect to source
    top -= anchorOffsets[options.anchor[0].charAt(0)] * sourceBox.height;
    left -= anchorOffsets[options.anchor[0].charAt(1)] * sourceBox.width;

    //alignment with respect to target
    top += anchorOffsets[options.anchor[1].charAt(0)] * targetBox.height;
    left += anchorOffsets[options.anchor[1].charAt(1)] * targetBox.width;

    //add offset to final coordinates
    left += options.offset[0];
    top += options.offset[1];

    $(this).css({
    left: left + 'px',
    top: top + 'px'
    });

    }

    ReplyDelete
  5. UserMay 30, 2012 at 3:54 AM

    Something like this?

    $(menu).css("top", targetE1.y + "px");
    $(menu).css("left", targetE1.x - widthOfMenu + "px");

    ReplyDelete
  6. UserMay 30, 2012 at 3:54 AM

    This works for me:

    var posPersonTooltip = function(event) {
    var tPosX = event.pageX - 5;
    var tPosY = event.pageY + 10;
    $('#personTooltipContainer').css({top: tPosY, left: tPosX});

    ReplyDelete
  7. UserMay 30, 2012 at 3:54 AM

    Why complicating too much? Solution is very simple

    css:

    .active-div{
    position:relative;
    }

    .menu-div{
    position:absolute;
    top:0;
    right:0;
    display:none;
    }


    jquery:

    $(function(){
    $(".active-div").hover(function(){
    $(".menu-div").prependTo(".active-div").show();
    },function(){$(".menu-div").hide();
    })


    It works even if,


    Two divs placed anywhere else
    Browser Re-sized

    ReplyDelete

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