How to get xy coordinates of child element from parent element in jquery?

问题

How to get xy coordinates of child element from parent element, and not the(body)? How to get x value from DIV B to DIV A, so when window resizes, the values stay true???

var startPos = $("#divB").position();
$("#divB").draggable({ 
     containment: 'parent',
     stop: function(event, ui) {
        var stopPos = $(this).position();
        $("#firstInput").val((stopPos.left - startPos.left));
     }
});

Is there a method to get this values directly and not from xy coordinates of whole screen?

回答1:

To get the offset of a child element relative to its' parent use position():

$("#child").position().left;
$("#child").position().top;

The caveat on this being that the parent must NOT be position: static for this to work. If the parent is static, jQuery will just return the offset() - which I assume is what is happening in your code.

static is the default for most block elements, so you'll need to set position to fixed, absolute or relative on the parent in your CSS.

来源：https://stackoverflow.com/questions/8446179/how-to-get-xy-coordinates-of-child-element-from-parent-element-in-jquery