複製代碼 代碼如下:
function forEach(object, block, context, fn) {
if (object == null) return;
if (!fn) {
if (typeof object == "function" && object.call) {
//遍曆普通對象
fn = Function;
} else if (typeof object.forEach == "function" && object.forEach != arguments.callee) {
//如果目標已經實現了forEach方法，則使用它自己的forEach方法（如標準遊覽器的Array對象）
object.forEach(block, context);
return;
} else if (typeof object.length == "number") {
// 如果是類數組對象或IE的數組對象
_Array_forEach(object, block, context);
return;
}
}
_Function_forEach(fn || Object, object, block, context);
};
function _Array_forEach(array, block, context) {
if (array == null) return;
var i = 0,length = array.length;
if (typeof array == "string") {
for (; i < length; i++) {
block.call(context, array.charAt(i), i, array);
}
}else{
for (;i < length; i++) {
block.call(context, array[i], i, array);
}
}
};
_Function_forEach = function(fn, object, block, context) {
// 這裡的fn恒為Function
for (var key in object) {
//只遍曆區域屬性
if (object.hasOwnProperty(key)) {
//相當於 block(object[key], key)
block.call(context, object[key], key, object);
}
}
};
原作者的一些例子（我翻牆扒過來了！）：
複製代碼 代碼如下:
function print(el,index){
alert(index+" : "+el)
}
forEach ([1, 2, 3], print);
forEach ({a: "aa", b: "bb",c: "cc"}, print);
forEach ("司徒正美", print);
forEach(document.styleSheets,function(el){
if(el.href) alert(el.href)
});
<script> function forEach(object, block, context, fn) { if (object == null) return; if (!fn) { if (typeof object == "function" && object.call) { //遍曆普通對象 fn = Function; } else if (typeof object.forEach == "function" && object.forEach != arguments.callee) { //如果目標已經實現了forEach方法，則使用它自己的forEach方法（如標準遊覽器的Array對象） object.forEach(block, context); return; } else if (typeof object.length == "number") { // 如果是類數組對象或IE的數組對象 _Array_forEach(object, block, context); return; } } _Function_forEach(fn || Object, object, block, context); }; function _Array_forEach(array, block, context) { if (array == null) return; var i = 0,length = array.length; if (typeof array == "string") array = array.split(""); for (;i < length; i++) { block.call(context, array[i], i, array); } }; _Function_forEach = function(fn, object, block, context) { // 這裡的fn恒為Function for (var key in object) { //只遍曆區域屬性 if (object.hasOwnProperty(key)) { //相當於 block(object[key], key) block.call(context, object[key], key, object); } } }; function print(el,index){ alert(index+" : "+el) } forEach ([1, 2, 3], print); forEach ({a: "aa", b: "bb",c: "cc"}, print); forEach ("司徒正美", print); forEach(document.styleSheets,function(el){ if(el.href) alert(el.href) }); </script>
[Ctrl+A 全選 注:如需引入外部Js需重新整理才能執行]
複製代碼 代碼如下:
function Person(name, age) {
this.name = name || "";
this.age = age || 0;
};
Person.prototype = new Person;
var fred = new Person("Fred", 38);
fred.language = "English";//極晚綁定
fred.wife = "Wilma";//極晚綁定
forEach(fred,print)
<script type="text/javascript"> function forEach(object, block, context, fn) { if (object == null) return; if (!fn) { if (typeof object == "function" && object.call) { //遍曆普通對象 fn = Function; } else if (typeof object.forEach == "function" && object.forEach != arguments.callee) { //如果目標已經實現了forEach方法，則使用它自己的forEach方法（如標準遊覽器的Array對象） object.forEach(block, context); return; } else if (typeof object.length == "number") { // 如果是類數組對象或IE的數組對象 _Array_forEach(object, block, context); return; } } _Function_forEach(fn || Object, object, block, context); }; function _Array_forEach(array, block, context) { if (array == null) return; var i = 0,length = array.length; if (typeof array == "string") array = array.split(""); for (;i < length; i++) { block.call(context, array[i], i, array); } }; _Function_forEach = function(fn, object, block, context) { // 這裡的fn恒為Function for (var key in object) { //只遍曆區域屬性 if (object.hasOwnProperty(key)) { //相當於 block(object[key], key) block.call(context, object[key], key, object); } } }; function print(el,index){ alert(index+" : "+el) } function Person(name, age) { this.name = name || ""; this.age = age || 0; }; Person.prototype = new Person; var fred = new Person("Fred", 38); fred.language = "English";//極晚綁定 fred.wife = "Wilma";//極晚綁定 forEach(fred,print) </script>
[Ctrl+A 全選 注:如需引入外部Js需重新整理才能執行]
