返回到：Prototype – 元素对象
如果指定的索引与cssRule 匹配，则此方法返回元素的前一个兄弟元素或索引的第一个元素。如果未提供 cssRule，则考虑所有先前的兄弟姐妹。如果没有以前的兄弟符合这些条件，则返回 undefined。
语法
element.previous([cssRule][, index = 0] );
返回值
返回 HTML 元素。如果没有以前的兄弟符合这些条件，则返回 undefined。
例子
HTML
x
45
45
1
<html>2
<head>3
<title>Prototype examples</title>4
<script type = "text/javascript" src = "/javascript/prototype.js"></script>5
6
<script>7
function showResult() {8
var str = $('saying').previous();9
alert( "$('saying').previous() " + str.innerHTML );10
11
var str = $('saying').previous(0);12
alert( "$('saying').previous(0) " + str.innerHTML );13
14
var str = $('saying').previous('h3');15
alert( "$('$('saying').previous('h3') " + str.innerHTML );16
17
var str = $('ida-red').previous( '.yummy');18
alert( "$('ida-red').previous( .yummy ) " + str.innerHTML );19
20
var str = $('ida-red').previous( 5 );21
alert( "$('ida-red').previous() " + str );22
}23
</script>24
</head>25
26
<body>27
<p>Click the button to see the result.</p>28
29
<ul id = "fruits">30
<li id = "apples">31
<h3 id = "title">Apples</h3>32
<ul id = "list-of-apples">33
<li id = "golden-delicious">Golden Delicious</li>34
<li id = "mutsu">Mutsu</li>35
<li id = "mcintosh" class = "yummy">McIntosh</li>36
<li id = "ida-red" class = "yummy">Ida Red</li>37
</ul>38
<p id = "saying">An apple a day keeps the doctor away.</p> 39
</li>40
</ul>41
<br />42
43
<input type = "button" value = "Show Result" onclick = "showResult();"/>44
</body>45
</html>返回到：Prototype – 元素对象
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作者：terry，如若转载，请注明出处：https://www.web176.com/prototype_api/9055.html
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