使用 jQuery 隐藏元素； 我应该使用哪种方法，为什么？

Question

What is the difference between these two methods?

$("div span").hide();

$("div > span").hide();

Any impact on performance?

Answer 1

The first will hide all <span> s found anywhere under the <div> . The second will only hide <span> s that are immediate children of the <div> .

jQuery child-selector

Answer 2

On the performance aspect, it may depend upon the exact HTML, but I found the div > span selector to be about 30% faster in this jsperf test . That may be because it only has to look in the children of each div rather than through the whole DOM.

But, it's probably not enough of a speed difference to matter in most cases.