Question

I have a big piece of code that needs to be inserted into DOM at some point. The code also contain some variables:

<ul id="info'+value+'" class="info"><li class="hide"></li><li class="lock"><ul>
// just a piece of the code with variable "value"

Right now I am doing:

var codeToInsert = "<some code/>"
codeToInsert.insertAfter('#someID');

Is there a better way to do it from the performance point of view?

Answer 1

If you want to insert big piece of code, use jQuery for its selector and then use the innerHTML DOM property – it is the fastest way to insert a big chunk of HTML.
Do not wrap the string that is to be inserted into JQuery, leave it as a string.

E.g.: $('#somePlaceholder')[0].innerHTML = myHTMLString;.

http://www.quirksmode.org/dom/w3c_html.html:

In general innerHTML is faster than normal DOM methods because the HTML parser is always faster than the DOM engine. If you want to do complicated changes, use innerHTML. (For simple changes it does not really matter which method you use, although innerHTML remains theoretically faster.)

If you do string concatenation in JS, create an array, push() the parts and join() at the end instead of appending with e.g. += or +. It makes a difference esp. in IE.