<!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> <title>无标题页</title> </head> <body> <script type="text/javascript"> var start=0; var end=0; function add(){ alert(start+"/n"+end); 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; 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> <form action="a.cgi"> <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)" 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> </form> </body> </html>