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javascript定义变量时带var与不带var的区别分析_javascript技巧

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Release： 2016-05-16 16:20:56
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本文实例分析了javascript定义变量时带var与不带var的区别。分享给大家供大家参考。具体分析如下：

直接看实例里说明：

复制代码 代码如下:

严格来说：函数体内不带var，并不是指定义一个变量，而是进行变量赋值，即var abc;abc=8。在函数体内如果进行赋值 abc=80（不带var），实际过程是这样的——该语句先在函数体内查找变量abc，如果找不到，它会往上在函数体外继续查找变量abc，如果还是找不到，最后没有办法，只能在函数体外定义变量var abc。

所以，为什么

复制代码 代码如下:
function test(){
 abc = 80;
}

能够在函数外部直接调用变量abc，也就是这么一个原因。

希望本文所述对大家的javascript程序设计有所帮助。

Related labels：
javascript var the difference variable definition
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