<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script src='../jquery.js'></script>
<style>
.hide{display:none}
.test{background:green}
</style>
</head>
<body>
<div id='test'>ttttt</div>
<input type='text' id='adress' value='请输入' />
<script>
$(function(){
$('#adress').focus(function(){
var text=$(this).val();
if(text=='请输入'){
$(this).val('');
}
});
$('#adress').blur(function(){
var text=$(this).val();
if(text==''){
$(this).val('请输入');
}
});
});
</script>
</body>
</html>