javascript实现textarea中光标处插入字符的实现[兼容ie和firefox]（来自网络）

 因项目需要，需要在多行文本框中的光标位置插入字符，利于js的 document.selection属性很快就实现，但发现在firefox中无法兼容selection属性，网上找了很久也没有找到合适的方法，经过研究，改出了兼容ie和FF的完美解决方案
代码如下：

<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> function AddText(str) { var ubb = document.getElementById( " TxtContent " ); var ubbLength = ubb.value.length; ubb.focus(); if ( typeof document.selection != " undefined " ) { document.selection.createRange().text = str; } else { ubb.value = ubb.value.substr( 0 ,ubb.selectionStart) + str + ubb.value.substring(ubb.selectionStart,ubbLength); } }

例如：

<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> function Underline() { var tUnderline = prompt( " 请输入要设置的下划线文字\n标签:[u][/u] " , "" ) if (tUnderline == "" || tUnderline == null ) { return ; } tUnderline = " [u] " + tUnderline + " [/u] " AddText(tUnderline); }

HTML部分：

<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> < a href ="javascript:Underline();void(0)" >< img src ="Images/Style/underline.gif" alt ="下线线" border ="0" /></ a >

注：1、TxtContent为textarea的ID，函数str参数为要插入的字符
2、在ie6.0和FF2.0中调试通过！！