本文介绍了调用函数和引用函数之间的区别?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
查看以下代码:
window.onload = someFunction;
很多时候我看到使用这种代码甚至我都使用相同的代码。但是,仍有一些事情尚不清楚。
Many times I see the use of this kind of code and even I use the same. But, there are still few things unclear.
- 上面是一旦页面加载就调用
someFunction
。但是,我们不应该用括号()
来调用函数吗? - 根据我的理解,我们只是分配
someFunction
到window.onload
,因此我们可以或不应该调用window.onload()
; - 是否有这种情况,当
functionName()
和functionName
becames可互换。因为在很多地方和各种API,我看到调用函数没有括号。
- The above is a call to
someFunction
as soon as the page loads, right. But, aren't we supposed to call a function with brackets()
? - From my understanding, we are just assigning
someFunction
towindow.onload
, therefore can we or shouldn't we callwindow.onload()
; - Are there such cases, when
functionName()
andfunctionName
becames interchangeable. Because at many places, and in various API, I have seen calling the function without brackets.
推荐答案
你不是调用这个函数,你告诉浏览器 调用哪个函数,onload。
You're not calling the function, you're telling the browser which function to call, onload.
引用函数并调用函数永远不可互换:它们完全不同。
Referencing a function and calling a function are never interchangeable: they're completely different things.
但是,您可以调用返回的函数 a function:
You may, however, call a function that returns a function:
function getFunction() {
return function() {
alert("I'm the real onload function.");
};
}
window.onload = getFunction();
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