$.each()與$(selector).each()不同, 後者專用于jquery對象的周遊, 前者可用于周遊任何的集合(無論是數組或對象),如果是數組,回調函數每次傳入數組的索引和對應的值(值亦可以通過this 關鍵字擷取,但javascript總會包裝this 值作為一個對象—盡管是一個字元串或是一個數字),方法會傳回被周遊對象的第一參數.
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//例子:———傳入數組
<!DOCTYPE html>
<html>
<head>
<script src=”http://code.jquery.com/jquery-latest.js”></script>
</head>
<body>
<script>
$.each([52, 97], function(index, value) {
alert(index + ‘: ‘ + value);
});
</script>
</body>
</html>
//輸出
0: 52
1: 97
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//例子:———如果一個映射作為集合使用,回調函數每次傳入一個鍵-值對
<!DOCTYPE html>
<html>
<head>
<script src=”http://code.jquery.com/jquery-latest.js”></script>
</head>
<body>
<script>
var map = {
‘flammable’: ‘inflammable’,
‘duh’: ‘no duh’
};
$.each(map, function(key, value) {
alert(key + ‘: ‘ + value);
});
</script>
</body>
</html>
//輸出
flammable: inflammable
duh: no duh
---------------------------------------------------
//例子:———回調函數中 return false時可以退出$.each(), 如果傳回一個非false 即會像在for循環中使用continue 一樣, 會立即進入下一個周遊
<!DOCTYPE html>
<html>
<head>
<style>
div { color:blue; }
div#five { color:red; }
</style>
<script src=”http://code.jquery.com/jquery-latest.js”></script>
</head>
<body>
<div id=”one”></div>
<div id=”two”></div>
<div id=”three”></div>
<div id=”four”></div>
<div id=”five”></div>
<script>
var arr = [ "one", "two", "three", "four", "five" ];//數組
var obj = { one:1, two:2, three:3, four:4, five:5 }; // 對象
jQuery.each(arr, function() { // this 指定值
$(“#” + this).text(“Mine is ” + this + “.”); // this指向為數組的值, 如one, two
return (this != “three”); // 如果this = three 則退出周遊
});
jQuery.each(obj, function(i, val) { // i 指向鍵, val指定值
$(“#” + i).append(document.createTextNode(” – ” + val));
});
</script>
</body>
</html>
// 輸出
Mine is one. – 1
Mine is two. – 2
Mine is three. – 3
- 4
- 5
---------------------------------------------------
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