用JavaScript实现的文本框光标定位

时间：2007-02-17 来源：PHP爱好者

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>光标位置</title>
<style>
INPUT{border: 1 solid #000000}
BODY,TABLE{font-size: 10pt}
</style>
</head>
<body>
<table border="0" width="700" cellspacing="0" cellpadding="0">
<tr>
<td width="479" rowspan="7">
点击 TextArea 实现光标定位
<p>
<textarea rows="7" cols="49" id="box" onclick=tellPoint()>我怕来不及我要抱着你，直到感觉你的绉纹有了岁月的痕迹，直到视线变得模糊直到不能呼吸
为了你我愿意
动也不能动也要看着你，直到感觉你的发线有了白雪的痕迹，直到肯定你是真的直到失去力气让我们形影不离
如果全世界我也可以放弃，至少还有你值得我去珍惜而你在这里就是生命的奇迹
也许全世界我也可以忘记，就是不愿意失去你的消息你掌心的痣我总记得在哪里
我们好不容易我们身不由已，我怕时间太快不够将你看仔细，我怕时间太慢日夜担心失去你恨不得一夜之间白头永不分离
</textarea>

function movePoint()
{
var pn = parseInt(pnum.value);

if(isNaN(pn))
return;

var rng = box.createTextRange();

rng.moveStart("character",pn);

rng.collapse(true);

rng.select();

returnCase(rng)

}

function tellPoint()
{
var rng = event.srcElement.createTextRange();

rng.moveToPoint(event.x,event.y);
rng.moveStart("character",-event.srcElement.value.length)

pnum.value = rng.text.length

returnCase(rng)
}

function returnCase(rng)
{
bh.innerText = rng.boundingHeight;
bl.innerText = rng.boundingLeft;
bt.innerText = rng.boundingTop;
bw.innerText = rng.boundingWidth;
ot.innerText = rng.offsetTop;
ol.innerText = rng.offsetLeft;
t.innerText = rng.text;
}

function selectText(sp,ep)
{
sp = parseInt(sp)
ep = parseInt(ep)

if(isNaN(sp)||isNaN(ep))
return;

var rng = box.createTextRange();

rng.moveEnd("character",-box.value.length)
rng.moveStart("character",-box.value.length)

rng.collapse(true);

rng.moveEnd("character",ep)
rng.moveStart("character",sp)

rng.select();

returnCase(rng);
}

var rg = box.createTextRange();

function findText(tw)
{
if(tw=="")
return;

var sw = 0;

if(document.selection)
{
sw = document.selection.createRange().text.length;
}

rg.moveEnd("character",box.value.length);

rg.moveStart("character",sw);

if(rg.findText(tw))
{
rg.select();

returnCase(rg);
}

if(rg.text!=tw)
{
alert("已经搜索完了")
rg = box.createTextRange()
}

}

</script>
</p>
<p></p>
光标位置：<input type="text" value="0" id="pnum" size="8"> <input type="button" onclick="movePoint()" value="移动光标到指定位置">
<p></p>
选择指定范围：<input type="text" size="9" id="sbox"> -- <input type="text" size="9" id="ebox"> <input type="button" onclick="selectText(sbox.value,ebox.value)" value="选择">
<p></p>
选择查找字符：<input type="text" value="" id="cbox" size="8"> <input type="button" onclick="findText(cbox.value)" value="查找下一个并选择">

</td>
<td width="217">boundingHeight: <span id="bh"></span></td>
</tr>
<tr>
<td width="217">boundingWidth: <span id="bw"></span></td>
</tr>
<tr>
<td width="217">boundingTop: <span id="bt"></span></td>
</tr>
<tr>
<td width="217">boundingLeft: <span id="bl"></span></td>
</tr>
<tr>
<td width="217">offsetLeft: <span id="ol"></span> </td>
</tr>
<tr>
<td width="217">offsetTop: <span id="ot"></span> </td>
</tr>
<tr>
<td width="217">text: <span style="position: absolute; z-index: 10" id="t"></span> </td>
</tr>
</table>
</body>

</html>

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