[转] 修补textarea的focus()时的光标位置 _Web前端

[转] 修复textarea的focus()时的光标位置
<!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> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>textarea的focus修复</title>
<style type="text/css">
  p {
    background-color:#F7F9FA;
    border:1px dashed #8CACBB;
    padding:5px;
    line-height:1.5em;
  }
</style>
<script type="text/javascript" src="./yahoo-dom-event.js"></script>
</head> 

<body>
<p>测试情景：对已有内容的textarea执行focus()<br />
  测试结果：只有Firefox（gecko内核）能将光标定位在文本最后</p>
<textarea name="" cols="50" rows="10" id="textarea">预置内容预置内容</textarea><br />
<label> 
    <input type="submit" name="button" id="button" value="focus修复"    /> 
</label>

<script type="text/javascript"> 
  var textarea = document.getElementById("textarea"),
    button = document.getElementById("button");
  textarea.focus();
  button.onclick = function(){
    if(YAHOO.env.ua.ie){
      var rng = textarea.createTextRange();
      rng.text = textarea.value;
      rng.select();
      rng.collapse(false);
    }else if (YAHOO.env.ua.webkit){
      textarea.select();
      window.getSelection().collapseToEnd();
    }else{
      textarea.focus();
    }
  };
</script>
</body> 
</html>