var comm={ getPositionForInput:function(ctrl){ //普通文本框 var CaretPos = 0; if (document.selection) { // IE Support ctrl.focus(); var Sel = document.selection.createRange(); Sel.moveStart('character', -ctrl.value.length); CaretPos = Sel.text.length; }else if(ctrl.selectionStart || ctrl.selectionStart == '0'){// Firefox support CaretPos = ctrl.selectionStart; } return (CaretPos); }, getPositionForTextArea:function(ctrl) { //多行文本框 var CaretPos = 0; if(document.selection) {// IE Support ctrl.focus(); var Sel = document.selection.createRange(); var Sel2 = Sel.duplicate(); Sel2.moveToElementText(ctrl); var CaretPos = -1; while(Sel2.inRange(Sel)){ Sel2.moveStart('character'); CaretPos++; } }else if(ctrl.selectionStart || ctrl.selectionStart == '0'){// Firefox support CaretPos = ctrl.selectionStart; } return (CaretPos); }, setCursorPosition:function(ctrl, pos){ //设置光标位置函数 if(ctrl.setSelectionRange){ ctrl.focus(); ctrl.setSelectionRange(pos,pos); }else if (ctrl.createTextRange) { var range = ctrl.createTextRange(); range.collapse(true); range.moveEnd('character', pos); range.moveStart('character', pos); range.select(); } }, getStrLength:function(str){ return str.length; }, process:function( id,targetId ){ //test var no = document.getElementById(id).value; setCursorPosition(document.getElementById(targetId),no); } }
使用方法：
<body> <div class="title">JavaScript 获取/设置光标位置,兼容Input&&TextArea：</div> <div class="title">单行文本框</div> <p><input class="input" id="textbox" name="textbox" value="Hi,www.jb51.net!!!" /></p> <input type="button" onclick="alert( getPositionForInput( document.getElementById('textbox') ) )" value="Get Position"> 输入位置: <input type="text" id="no1" size="1" /><input type="button" onclick="process('no1','textbox');" value="Set Position"> <div class="title">多行文本框</div> <textarea id="zhangdanNum" name="zhangdanNum" style="height:66px;246px;overflow:hidden">Hi,CssRain!!!</textarea> <input type="button" onclick="alert( getPositionForTextArea( document.getElementById('zhangdanNum') ) )" value="Get Position"> 输入位置: <input type="text" id="no2" size="1" /><input type="button" onclick="process('no2','zhangdanNum');" value="Set Position"> </body>
感谢原文博主！