javascript - jQuery appending an array of elements

Question

For the purpose of this question lets say we need to append() 1000 objects to the body element.

You could go about it like this:

for(x = 0; x < 1000; x++) {
    var element = $('<div>'+x+'</div>');
    $('body').append(element);
}

This works, however it seems inefficient to me as AFAIK this will cause 1000 document reflows. A better solution would be:

var elements = [];
for(x = 0; x < 1000; x++) {
    var element = $('<div>'+x+'</div>');
    elements.push(element);
}
$('body').append(elements);

However this is not an ideal world and this throws an error Could not convert JavaScript argument arg 0 [nsIDOMDocumentFragment.appendChild]. I understand that append() can't handle arrays.

How would I using jQuery (I know about the DocumentFragment node, but assume I need to use other jQuery functions on the element such as .css()) add a bunch of objects to the DOM at once to improve performance?

Answer 1

You could use an empty jQuery object instead of an array:

var elements = $();
for(x = 0; x < 1000; x++) {
    elements = elements.add('<div>'+x+'</div>');
    // or 
    // var element = $('<div>'+x+'</div>');
    // elements = elements.add(element);
}
$('body').append(elements);

This might be useful if you want to do stuff with newly generated element inside the loop. But note that this will create a huge internal stack of elements (inside the jQuery object).

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It seems though that your code works perfectly fine with jQuery 1.8.