Javascript-动态更改函数的内容 [英] Javascript - Dynamically change the contents of a function
问题描述
我具有此功能(在页面加载时)使用"css" jQuery方法更改边距...
I have this function that (on page load) changes my margin using the "css" jQuery method...
function page_change() {
var h = window.location.hash;
switch (h) {
case 'home':
$('.page-slide-box').css({marginLeft: 0});
break;
case 'history':
$('.page-slide-box').css({marginLeft: '-820px'});
break;
// more cases here.....
}
}
...但是在页面加载后,我想动画更改.我当时想我可以使用replace()更改现有功能(而不是编写另一个冗余功能),就像这样:
...but after the page is loaded, I'd like to animate the change instead. I was thinking I could alter the existing function using replace() (rather than writing another redundant function), like so:
window.onhashchange = function() {
var get = page_change.toString();
var change = get.replace(/css/g, 'animate');
page_change();
}
这在我的page_change()函数中成功将"css"的所有实例更改为动画".替换字符串后,如何动态更改此函数?还是这只是一个坏主意?
This successfully changes all instances of "css" to "animate" in my page_change() function. How do I get this function to change dynamically once I've replaced the strings? Or is this just a bad idea?
推荐答案
在您的示例中,我想这是一个糟糕的主意.为什么不简单地定义一个可以同时执行这两个功能的函数,并相应地使用它:
In your example, I'd say this is a terrible idea. Why not simply define 1 function that can do both, and use it accordingly:
var page_change = function(e)
{
var method = e instanceof Event ? 'animate' : 'css';
switch (location.hash)
{
case 'home':
$('.page-slide-box')[method]({marginLeft: 0});
break;
//and so on...
}
};
直接调用此函数,它将设置css,如下所示使用它:
call this function directly, and it'll set the css, use it like so:
window.onhaschange = page_change;
,它将变为animate
,而不是使用css
方法.容易
and it'll animate
instead of use the css
method. Easy
如果要轻松测试,可以尝试以下方法:
If you want to test this easily, you could try this:
var page_change = function(e)
{
var method = e instanceof Event ? 'animate' : 'css';
console.log(method);
};
document.body.onclick = page_change;
page_change();//logs css
//click the body and...
//animate will be logged
基本上,这就是它的工作方式.
定义这样的函数(匿名函数,分配给变量或由var 引用)的另一个好处是,您可以轻松地将新函数分配给相同的变量:
That's, basically, how this works.
The added benefit of defining a function like this (anonymous function, assigned to a variable or referenced by a var) is that you can easily assign a new function to that same variable:
var myFunc = function(){ console.log('foo');};
myFunc();//logs foo
myFunc = function(){console.log('bar')};
myFunc();//logs bar
这当然也可以为您服务.您甚至可以存储旧功能:
This might work for you, too... of course. You can even store the old function:
var myFunc = function(){ console.log('foo');};
myFunc();//logs foo
var oldMyFunc = myFunc;
myFunc = function(){console.log('bar')};
myFunc();//logs bar
oldMyFunc();//logs foo
试一试,找到最适合您需求的方法(这很可能是我在此答案中讨论的内容的组合)
Play around with this for a while, to find the approach that fits your needs best (it could well be a combination of the things I talked about in this answer)
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