在jquery ready块内定义的函数与外部函数之间有什么区别？ [英] what is the difference between a function defined inside jquery ready block and one outside
问题描述
我用onclick属性向一个按钮注册一个函数，并在$（）block中定义这个函数（我知道这是一个不好的习惯，这只是一个例子），当我点击按钮时，会发生一个错误： Uncaught ReferenceError：hello没有定义。这是我的代码：
I register a function to a button with onclick attribute, and define this function in $() block(I know it is a bad practice, and it is just an example), when I click the button, an error occurs: Uncaught ReferenceError: hello is not defined. Here is my code:
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script type="text/javascript">
$(function(){
function hello(){
alert('hello');
}
});
</script>
</head>
<body>
<input type="button" id="btn" value="click" onclick="hello()"/>
</body>
如果我将hello函数代码放在$（）块外面，它就可以工作。我知道$（）是在解析DOM时执行的，当我点击按钮时，DOM必须已经被解析，那么为什么它会报错？
Thanks。
if I put hello function code out of $() block, it works. I know $() is executed when DOM is parsed, when I click the button, the DOM must already has been parsed, so why it reports an error? Thanks.
推荐答案
（没有定义）在 $。ready 块内保证在DOM准备好被访问/操作后执行。
There is no difference, except that functions executed (not defined) inside a $.ready block are guaranteed to execute after the DOM is ready to be accessed/manipulated.
你的问题是范围界定问题之一;你已经创建了一个局部函数，它在你的事件处理的全局范围内不可访问。
Your issue is one of scoping; you've created a local function which isn't accessable at the global scope where your event is being handled.
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