JQMIGRATE: jQuery.fn.offset() requires an element connected to a document

问题

I have a site which used jquery 1.x.... Now, I have started using jquery 3.x in this site..... to solve any migration issues, I have installed JQMigrate.

One of the messages it shows in console window is "JQMIGRATE: jQuery.fn.offset() requires an element connected to a document".

I am not sure how I can solve it. The only thing that is said as a "solution" is: "Do not attempt to get or set the offset information of invalid input."

That is obvious, but what does it mean in practice? if I have, for example,

var parentOffset = $offsetParent.offset();

Should I write that line something like this?

var parentOffset = $offsetParent ? $offsetParent.offset() : 0;

Is it really necessary since I know that $offsetParent is always a valid input.

Regards Jaime

回答1:

I just came across this same line of code.

The problem here is that the $offsetParent element is not part of the document.

Instead of checking $offsetParent.length we want to make sure this element is actually part of the document

// As of jQuery 3.0, .offset() only works for elements that are currently
// in the document. In earlier versions, this would return the value below
// but in jQuery 3.0 this throws an error.
var parentOffset = {top: 0, left: 0};

// If the element is in the document we are safe to use .offset()
if(document.body.contains($offsetParent[0])) {
    parentOffset = $offsetParent.offset();
}

See https://github.com/jquery/jquery-migrate/blob/master/warnings.md#jqmigrate-jqueryfnoffset-requires-an-element-connected-to-a-document for more information on this change.

回答2:

if(jQueryObject) will always be truthy even if a match doesn't exist for the selector or method used to obtain the element

Check it's length instead

var parentOffset = $offsetParent.length ? $offsetParent.offset() : 0;

来源：https://stackoverflow.com/questions/51681100/jqmigrate-jquery-fn-offset-requires-an-element-connected-to-a-document

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jquery

jqmigrate