<script>
function search(form){
var s_text=document.getElementById("s_text").value
if (s_text == "" || s_text == undefined || s_text == null){alert("请输入搜索词");}else{form.action="/?wd="+""+s_text+"";form.submit();}
}
</script>
<form method="POST" name="sform" id="sform">
<input type="text" id="s_text" size="20" placeholder="请输入搜索词">
<input type="submit" value="搜索" name="B1" onclick='search(this.parentNode);'></ul>
</div>
</form>