在javascript中使用全局变量 [英] Using a global variable in javascript
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问题描述
我的代码是这样的:
code> var number = null;函数playSong(artist,title,song,id)
{
alert('old number was:'+ [number] +'');
var number ='10';
alert(''+ [number] +'');
}
第一个警报总是返回'old number was:',而不是10. Shouldn 't它会在第二次函数调用时返回10吗?
解决方案使用
var
code>当设置number ='10'时,你每次都声明 number
作为局部变量。试试这个: var number = null;
函数playSong(artist,title,song,id)
{
alert('old number was:'+ [number] +'');
number ='10';
alert(''+ [number] +'');
}
How do I do this?
My code is something like this:
var number = null;
function playSong(artist,title,song,id)
{
alert('old number was: '+[number]+'');
var number = '10';
alert(''+[number]+'');
}
The first alert always returns 'old number was: ' and not 10. Shouldn't it return 10 on both alerts on the second function call?
解决方案
By using var
when setting number = '10', you are declaring number
as a local variable each time. Try this:
var number = null;
function playSong(artist,title,song,id)
{
alert('old number was: '+[number]+'');
number = '10';
alert(''+[number]+'');
}
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