JavaScript provides properties to get the position of an HTML element:
Htmlelement.offsetleft
Htmlelement.offsetheight
Note, however, that the values stored by these two properties are not the absolute position of the element relative to the entire browser canvas, but rather the relative position relative to the position of its parent element, which means that the values are computed by the 0,0 point in the upper-left corner of the parent element. So how do you get an absolute position for an HTML element, you can use the following function:
Copy Code code as follows:
Get the ordinate of an element
function GetTop (e) {
var offset=e.offsettop;
if (e.offsetparent!=null) offset+=gettop (e.offsetparent);
return offset;
}
Get the horizontal axis of an element
function GetLeft (e) {
var offset=e.offsetleft;
if (e.offsetparent!=null) offset+=getleft (e.offsetparent);
return offset;
}
The principle is to take advantage of the Htmlelement.offsetparent attribute, if the current element's parent element is not NULL (NULL), then add the current offsettop based on the original offsettop, then continue to get the parent element's offsettop, then add it, and finally recursively The ordinate of the element relative to the entire browser canvas. The horizontal axis is the same.
