javascript 获取 textarea 当前光标 并插入内容
作者: jiake0504 链接:http://jiake0504.javaeye.com/blog/249504 发表时间: 2008年10月06日
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<html> <head> <title>TEST</title> <style> body,td{ font-family: verdana, arial, helvetica, sans-serif; font-size: 12px; } </style> <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; var textLength = document.getElementById("ta").value.length; start = textLength; end = textLength; } 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> <table cellspacing="0" cellpadding="0"> <tr> <td>start: <input type="text" /></td> <td>end: <input type="text" /></td> </tr> <tr> <td colspan="2"> <textarea ></textarea> </td> </tr> <tr> <td><input type="text" /></td> <td><input type="button" onClick="add()" value="Add Text"/></td> </tr> </table> </body> </html>
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