Javascript变量作用域
请先看下题:
if(true)
{
a = 1;
}
alert(a); //输出啥?
if(true)
{
var a = 1;
}
alert(a); //这又输出什么?
在firefox3.5下,第一个输出1;第二个输出undefined!!!
为啥呢?呵呵,本人在此班门弄斧一下:
一般情况下缺省var声明时,默认该变量为全局变量。了解这句话,所有问题也就迎刃而解了!呵呵!
第一道题:变量a缺省var声明,而直接使用,故而默认为全局变量,输出1
第二道题:变量a,在if块中var声明,属局部变量,输出undefined!
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问:
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2.如何在JavaScript访问C#变量?
3.如何在C#中访问JavaScript的已有变量?
4.如何在C#中访问JavaScript函数?
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SCRIPT 标记
用于包含JavaScript代码.
属性
LANGUAGE 定义脚本语言
SRC 定义一个URL用以指定以.JS结尾的文件
window对象
每个HTML文档的顶层对象.
属性
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