如何检测函数是用javascript调用的 [英] how to detect a function was called with javascript
问题描述
我有一个javascript函数。
I have a javascript function.
如何检查：
-
如果调用了函数（在
< head>< / head>部分中有此函数），则不要调用函数
if function was called ( in
<head></head>section have this function), then not to call the function
如果未调用函数（在< head>< / head> 部分中没有此函数），则调用功能
if function was not called ( in <head></head> section haven't this function), then call the function
如 require_once 或 include_once PHP
推荐答案
两个选项：
静态变量以下是使用自调用函数在静态变量中创建静态变量（如C语言）的方法。
Static variables Here's how to create static (like in C) variables using self calling functions to store your static variables in a closure.
var myFun = (function() {
var called = false;
return function() {
if (!called) {
console.log("I've been called");
called = true;
}
}
})()
空函数替换运行后将函数设置为空函数。
Empty Function replacement Set the function to an empty function after it runs.
function callonce() {
console.log("I've been called");
arguments.callee = function() {};
}
抽象的想法这是一个返回一个函数的函数只调用一次的函数，这样我们就不用担心将锅炉板代码添加到每个函数中。
Abstract the idea Here's a function that returns a function that only gets called once, this way we don't have to worry about adding boiler plate code to every function.
function makeSingleCallFun(fun) {
var called = false;
return function() {
if (!called) {
called = true;
return fun.apply(this, arguments);
}
}
}
// Alternate implementation
function makeSingleCallFun(fun) {
return function() {
return fun.apply(this, arguments);
arguments.callee = function() {};
}
}
var myFun = makeSingleCallFun(function() {
console.log("I've been called");
});
myFun(); // logs I've been called
myFun(); // Does nothing
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