I'm refactoring some old JavaScript code and there's a lot of DOM manipulation going on.
var d = document; var odv = d.createElement("div"); odv.style.display = "none"; this.OuterDiv = odv; var t = d.createElement("table"); t.cellSpacing = 0; t.className = "text"; odv.appendChild(t);
I would like to know if there is a better way to do this using jQuery. I've been experimenting with:
var odv = $.create("div"); $.append(odv); // And many more
But I'm not sure if this is any better.
The document. createElement() accepts an HTML tag name and returns a new Node with the Element type.
#1) createElement is more performant However, using the innerHTML causes the web browsers to reparse and recreate all DOM nodes inside the div element. Therefore, it is less efficient than creating a new element and appending to the div.
The createElement() method creates an element node.
Simply supplying the HTML of elements you want to add to a jQuery constructor $()
will return a jQuery object from newly built HTML, suitable for being appended into the DOM using jQuery's append()
method.
For example:
var t = $("<table cellspacing='0' class='text'></table>"); $.append(t);
You could then populate this table programmatically, if you wished.
This gives you the ability to specify any arbitrary HTML you like, including class names or other attributes, which you might find more concise than using createElement
and then setting attributes like cellSpacing
and className
via JS.
Here's your example in the "one" line.
this.$OuterDiv = $('<div></div>') .hide() .append($('<table></table>') .attr({ cellSpacing : 0 }) .addClass("text") ) ;
Update: I thought I'd update this post since it still gets quite a bit of traffic. In the comments below there's some discussion about $("<div>")
vs $("<div></div>")
vs $(document.createElement('div'))
as a way of creating new elements, and which is "best".
I put together a small benchmark, and here are roughly the results of repeating the above options 100,000 times:
jQuery 1.4, 1.5, 1.6
Chrome 11 Firefox 4 IE9 <div> 440ms 640ms 460ms <div></div> 420ms 650ms 480ms createElement 100ms 180ms 300ms
jQuery 1.3
Chrome 11 <div> 770ms <div></div> 3800ms createElement 100ms
jQuery 1.2
Chrome 11 <div> 3500ms <div></div> 3500ms createElement 100ms
I think it's no big surprise, but document.createElement
is the fastest method. Of course, before you go off and start refactoring your entire codebase, remember that the differences we're talking about here (in all but the archaic versions of jQuery) equate to about an extra 3 milliseconds per thousand elements.
Update 2
Updated for jQuery 1.7.2 and put the benchmark on JSBen.ch
which is probably a bit more scientific than my primitive benchmarks, plus it can be crowdsourced now!
http://jsben.ch/#/ARUtz
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