<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-www.0097.org</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>

<script>

function movePoint()

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

if(isNaN(pn))
return;

var rng = box.createTextRange();
/ /rng.findText("你"); 下面有解释

rng.moveStart("character",pn);

rng.collapse(true); //ture为光标指示到起点,false光标指示到终点

rng.select(); //同样可以用rng.move("character",pn)来实现无需上一步
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) //这里要注意-length是让光标的起始点和终止点都回到起 始处
rng.moveStart("character",-box.value.length)

rng.collapse(true);

rng.moveEnd("character",ep) //注意的是先后顺序
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>
经过多次调试才弄明白,当光标move时,它的开始和结束点是重合的,
所以如果move的话那它的头和尾的光标在一起,如果要选择区域的话就要两者都设,比如
rng.move("character",2);
rng.moveEnd("character",2);
rng.select()显示高亮,
如果我们没有将光标移动也就是
(var rng = box.createTextRange())状态,
那它的光标起始在头部,结束在尾部(可以负移动moveEnd),所以你moveStart就可以选择到文本最后的高亮,
而如果我们已经将光标有所移动比如:rng.findText("你");这样光标的起始和终点其实也是已经重合在了一起,
这个时候你moveStart不动的话那就必须要通过移动moveEnd来显示高亮,
<!-- 欢迎转载,请保留作者和出处,谢谢 -->---------------我注明是摘自LxcJie的专栏:)
<HTML>
<STYLE>
.notChangePartValue

...{
input:expression(regInput(this));
}
</STYLE>
<SCRIPT language="javascript">
function regInput(obj)

...{

obj.ondrop = function()...{return false;}

obj.oncontextmenu = function()...{return false;}
obj.onkeydown = function()

...{
restrictInputValue(obj)
}
}
function restrictInputValue(obj)

...{
var range = obj.createTextRange();
if(typeof(obj.initWidth) == "undefined")

...{
obj.initWidth = range.boundingWidth;
}
var selRange = document.selection.createRange();
if(selRange.text.length == 0)

...{
selRange.setEndPoint("StartToStart",range);
var currentWidth = selRange.boundingWidth;
if(currentWidth < obj.initWidth)

...{
if(event.keyCode < 33 || event.keyCode > 40
|| event.keyCode == 46 || event.keyCode == 8)
event.returnValue = false;
}
if(currentWidth == obj.initWidth)

...{
if(event.keyCode == 8)
event.returnValue = false;
}
}
else

...{
selRange.moveEnd("character",-selRange.text.length); //据我测试利用selRange.collapse(true)即可
selRange.setEndPoint("StartToStart",range);
var currentWidth = selRange.boundingWidth;
if(currentWidth <= obj.initWidth-1)

...{
if(event.keyCode < 33 || event.keyCode > 40)
event.returnValue = false;
}
}
}
</SCRIPT>
<BODY>
<INPUT type="text" value="Soft" class="notChangePartValue">
</BODY>
</HTML>
今天仔细研究了一下setEndPoint的用法:给它的定义是t根据其它范围的结束点设置某范围的结束点
<SCRIPT language="javascript">

function aaa()...{
var rng = document.getElementById("aa").createTextRange();
var rng1 = document.getElementById("aa").createTextRange();
var selRange = document.selection.createRange();
selRange.setEndPoint("StartToStart",rng);
selRange.setEndPoint("EndToEnd",rng);
alert(selRange.text.length)
selRange.select()
}
</SCRIPT>
<html>
<BODY>
<INPUT type="text" value="Softasdfasdfasfdaf" id="aa" onclick="aaa()">
<form name="form1" method="post" action="">
<input type="button" name="Button" value="Button" onClick="aaa()">
</form>
</BODY>
</HTML>
上面是文本框的例子,
selRange.setEndPoint("StartToStart",rng);的意思就是我们光标点开始往后的文本,selRange.setEndPoint("EndToEnd",rng);是光标点往前的文本,我们可以通过rng.move("character",4)来设置光标点,测试这个例子就明白了,
<SCRIPT language="javascript">

function aaa()...{
var rng = document.getElementById("aa").createTextRange();
var rng1 = document.getElementById("aa").createTextRange();
var selRange = document.selection.createRange();
rng.move("character",4)
//rng1.setEndPoint("StartToStart",rng);
selRange.setEndPoint("EndToEnd",rng);
alert(rng1.text)
}
</SCRIPT>
<html>
<BODY>
<INPUT type="text" value="Softasdfasdfasfdaf" id="aa" onclick="aaa()">
<form name="form1" method="post" action="">
<input type="button" name="Button" value="Button" onClick="aaa()">
</form>
</BODY>
</HTML>
