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js: 实现Select的option上下移动

2015-08-20 23:25 746 查看
<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<title></title>

<script type="text/javascript">

function UpOrDown(direct, selectId) {//direct : 1:Up, -1:Down

var obj = document.getElementById(selectId);

var len = obj.length;

var index = obj.selectedIndex;

//如果:1.没有选中的项; 2.向上,但已是最上; 3.向下,但是最下,不作处理

if ( (index == -1) || (direct == -1 && index == 0) || (direct == 1 && index >= len - 1) )

return;

var swapIndex = index + direct;

var tempOptions = new Array();

for (var i = 0; i < len; i++){

tempOptions[tempOptions.length] = obj.options[i == index?swapIndex:(i == swapIndex?index:i)];

}

obj.options.length = 0;

for (var i = 0; i < len; i++)

obj.options.add(tempOptions[i]);

}

function UpOrDown2(direct, selectId) {//direct : 1:Up, 0:Down

var obj = document.getElementById(selectId);

var len = obj.length;

var index = obj.selectedIndex;

//如果:1.没有选中的项; 2.向上,但已是最上; 3.向下,但是最下,不作处理

if( (index == -1) || (direct == 1 && index == 0) || (direct == 0 && index >= len - 1) )

return;

var tempOptions = new Array();

//如是向上,得到自己上一个到最后的option数组;如是向下,得到自己到最后一个的option数组

for (var i = index - direct; i < len; i++)

tempOptions[tempOptions.length] = obj.options[i];

//去除刚才取得的部分

obj.options.length = index - direct;

//颠倒取两个option

obj.options.add(tempOptions[1]);

obj.options.add(tempOptions[0]);

//将余下的option全部加进来

for (var i = 2; i < tempOptions.length; i++)

obj.options.add(tempOptions[i]);

}

</script>

</head>

<body>

<table>

<tr>

<td>

<select id="Select1" size="100" style="width:100px;height:200px;">

<option>1</option>

<option>2</option>

<option>3</option>

<option>4</option>

<option>5</option>

</select>

</td>

<td>

<img id="imgUp" alt="Up" onclick="UpOrDown(-1,'Select1')" style="cursor:pointer;" /><br />

<img id="imgDown" alt="Down" onclick="UpOrDown(1,'Select1')" style="cursor:pointer;" />

</td>

<td>

<img id="img1" alt="Up2" onclick="UpOrDown2(1,'Select1')" style="cursor:pointer;" /><br />

<img id="img2" alt="Down2" onclick="UpOrDown2(0,'Select1')" style="cursor:pointer;" />

</td>

</tr>

</table>

</body>

</html>
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