​x
 
<html>
<head>
<script type="text/javascript">
function selText()
{
document.getElementById("myText").select()
}
</script>
</head>
​
<body>
<form>
<input size="25" type="text" id="myText" value="选定我吧！">
<input type="button" value="选择文本" onclick="selText()"> 
</form>
</body>
​
</html>
​