temporarily removing and later reinserting a DOM element?

Question

Hello,

Is there some jquery magic that will let me do the following:

[0- define some element in HTML (eg, a unchecked checkbox)]

1- update its DOM element by setting one of its attributes using .attr() (eg, by setting its "checked" attribute using .attr('checked', true) )

2- temporarily remove that element from the DOM

3- reinsert the original element into the DOM, while preserving all its properties (ie, so that it is checked as it was at the end of step 1-- NOT like it was when initially defined in the HTML)

The reason why I am interested in removing these elements from the DOM (rather than hiding them) is that I have noticed that it seems to improve performance a good bit. My page has three different "states" and only a third of the total number of DOM elements is needed in any given state. [I wish to keep it as a single page with different states rather than breaking it into three separate pages.]

Until now I had been removing and reinserting elements into the DOM by storing in a var the value of

$("#myElement").html()

and then removing it, but now I noticed that upon reinsertion of that HTML into the DOM the changes made [in step 1] had been "undone".

Is there a way to do this -- to temporarily remove unneeded stuff from the DOM in a way that preserves all its properties for later reinsertion?

thanks for any insight,

lara

Answer 1

You may use the clone method:

var els = $('.els'), saved = els.clone (true);
els.remove ();
// .... do other stuff
saved.appendTo ($('.wherever-you-want-to'));

That said, though, it's better to show & hide them (via display: none, for example), than to manipulate the DOM as it's very expensive. If you have to, use DOM insertion & removal (as above), rather than .html (), which recreated a node from the given string every time.

Answer 2

Just remove the element from the document and keep a reference to it. There's no need to clone it.

var el;

function removeEl() {
    el = $("#myElement")[0]; // Get the element itself
    el.parentNode.removeChild(el);
}

function reinsertEl(node) {
    node.appendChild(el);
}

As an aside since you mentioned it in your example, it's much simpler, clearer and faster to set the checked property of a checkbox directly rather than use attr(). There's no need to involve attributes at all and indeed jQuery's attr() usually doesn't. Just do $("#myElement")[0].checked = true;. It works in all mainstream browsers.