<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="jsCursorDemo._Default" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title> <script type="text/javascript"> var start = 0; var end = 0; function add() { var textBox = document.getElementById("ta"); var pre = textBox.value.substr(0, start); var post = textBox.value.substr(end); textBox.value = pre + document.getElementById("inputtext").value + post; } function savePos(textBox) { //如果是Firefox(1.5)的话，方法很简单 if (typeof (textBox.selectionStart) == "number") { start = textBox.selectionStart; end = textBox.selectionEnd; } //下面是IE(6.0)的方法，麻烦得很，还要计算上'/n' else if (document.selection) { var range = document.selection.createRange(); if (range.parentElement().id == textBox.id) { // create a selection of the whole textarea var range_all = document.body.createTextRange(); range_all.moveToElementText(textBox); //两个range，一个是已经选择的text(range)，一个是整个textarea(range_all) //range_all.compareEndPoints()比较两个端点，如果range_all比range更往左(further to the left)，则 //返回小于0的值，则range_all往右移一点，直到两个range的start相同。 // calculate selection start point by moving beginning of range_all to beginning of range for (start = 0; range_all.compareEndPoints("StartToStart", range) < 0; start++) range_all.moveStart('character', 1); // get number of line breaks from textarea start to selection start and add them to start // 计算一下/n for (var i = 0; i <= start; i++) { if (textBox.value.charAt(i) == '/n') start++; } // create a selection of the whole textarea var range_all = document.body.createTextRange(); range_all.moveToElementText(textBox); // calculate selection end point by moving beginning of range_all to end of range for (end = 0; range_all.compareEndPoints('StartToEnd', range) < 0; end++) range_all.moveStart('character', 1); // get number of line breaks from textarea start to selection end and add them to end for (var i = 0; i <= end; i++) { if (textBox.value.charAt(i) == '/n') end++; } } } document.getElementById("start").value = start; document.getElementById("end").value = end; } </script></head><body> <form id="form1" runat="server"> <div> <table border="1" cellspacing="0" cellpadding="0"> <tr> <td> start: <input type="text" id="start" size="3" /> </td> <td> end: <input type="text" id="end" size="3" /> </td> </tr> <tr> <td colspan="2"> <textarea id="ta" onkeydown="savePos(this);" onkeyup="savePos(this);" onmousedown="savePos(this);" onmouseup="savePos(this);" onfocus="savePos(this);" onmousemove="savePos(this);" rows="14" cols="50"></textarea> </td> </tr> <tr> <td> <input type="text" id="inputtext" /> </td> <td> <input type="button" onclick="add()" value="Add Text" /> </td> </tr> </table> </div> </form></body></html>
