Are there any speed/efficiency differences between the following two lines.
以下两行之间是否存在速度/效率差异？
$("table td:not(:first-child)")
and
和
$("table td").not(":first-child")
I would think that the first would be better since it is removes objects, but is there an actual difference and is it substantial.
我认为第一个会更好，因为它是删除对象，但是它是否存在实际差异并且是实质性的。
Thanks
谢谢
2 个解决方案
#1
25
As you can see from the jsperf test, :not is on average about twice as fast. Overall though this performance will likely be a very small part of your overall execution time.
正如你在jsperf测试中看到的那样：平均不是快两倍。总体而言，这种性能可能只占整体执行时间的很小一部分。
The jquery docs state:
jquery文档声明：
The .not() method will end up providing you with more readable selections than pushing complex selectors or variables into a :not() selector filter. In most cases, it is a better choice.
与将复杂选择器或变量推送到：not（）选择器过滤器相比，.not（）方法最终会为您提供更多可读选择。在大多数情况下，这是一个更好的选择。
So really it's up to you to decide if the fractions of a second you gain outweigh the readability.
所以真的由你决定你获得的一秒的分数是否超过可读性。
#2
13
Depends on the browser.
取决于浏览器。
Browsers that support querySelectorAll will get a performance boost with...
支持querySelectorAll的浏览器将通过...获得性能提升
$("table td:not(:first-child)")
...because it is a valid selector. Older browsers (IE7 and lower) will not.
...因为它是一个有效的选择器。较旧的浏览器（IE7及更低版本）不会。
You need to be careful with the :not() selector though. jQuery (Sizzle) extends it with non-standard selectors, so it's easy to break qSA.
你需要小心：not（）选择器。 jQuery（Sizzle）使用非标准选择器扩展它，因此很容易打破qSA。
#1
25
As you can see from the jsperf test, :not is on average about twice as fast. Overall though this performance will likely be a very small part of your overall execution time.
正如你在jsperf测试中看到的那样：平均不是快两倍。总体而言，这种性能可能只占整体执行时间的很小一部分。
The jquery docs state:
jquery文档声明：
The .not() method will end up providing you with more readable selections than pushing complex selectors or variables into a :not() selector filter. In most cases, it is a better choice.
与将复杂选择器或变量推送到：not（）选择器过滤器相比，.not（）方法最终会为您提供更多可读选择。在大多数情况下，这是一个更好的选择。
So really it's up to you to decide if the fractions of a second you gain outweigh the readability.
所以真的由你决定你获得的一秒的分数是否超过可读性。
#2
13
Depends on the browser.
取决于浏览器。
Browsers that support querySelectorAll will get a performance boost with...
支持querySelectorAll的浏览器将通过...获得性能提升
$("table td:not(:first-child)")
...because it is a valid selector. Older browsers (IE7 and lower) will not.
...因为它是一个有效的选择器。较旧的浏览器（IE7及更低版本）不会。
You need to be careful with the :not() selector though. jQuery (Sizzle) extends it with non-standard selectors, so it's easy to break qSA.
你需要小心：not（）选择器。 jQuery（Sizzle）使用非标准选择器扩展它，因此很容易打破qSA。