javascript问题中的var keywork [英] var keywork in javascript problem

问题描述

每个伙伴
我是Java脚本中的新手，并且想知道javascript中的var关键字用于什么用途?
用于定义变量或范围概念吗?请举个例子.
Thanks

hi every buddy
im new in java script and a want to know that var keyword in javascript use for what?
is using for define variable or scope concept?please give me an example .
thanks

推荐答案

它定义了一个变量，该变量有效地将其范围定义为当前块.

如果使用它，它将始终使用给定名称创建一个新变量，如果不使用它，则它将备份当前作用域，直到找到已经具有该名称的变量并使用它为止.或创建一个新变量(如果找不到).

我建议您尽可能使用var，因为如果您不打算在两个不同的函数中使用相同名称的全局变量，那么它将防止以后出现错误！

It defines a variable, which effectively defines it''s scope as the current block.

If you use it, then it always creates a new variable with the given name, if you don''t, then it looks back up the current scope(s) until it finds a variable with that name already and uses that instead. Or creates a new variable if it doesn''t find one.

I would recommend that you use var whenever you can, as it prevents mistakes later if you didn''t mean to use a global variable of the same name in two different functions!

这些是一些链接，您可以检查一下.
benalman.com
最佳实践
developer.mozilla.org/zh-CN /docs/JavaScript
www.tizag.com

these are some links, you can check it.
benalman.com
bestpractices
developer.mozilla.org/en-US/docs/JavaScript
www.tizag.com

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