<body>
<input type="text" name="" id="xm" value="请输入你的姓名" onclick="d()"/>
<select id="xb" name="xingbie">
<option >请选择</option>
<option value="nan">男</option>
<option value="nv">女</option>
</select>
<input type="submit" value="问候" onclick="a()"/>
</body>
<script type="text/javascript">
var x=document.getElementById("xm");
var y=document.getElementById("xb");
var b=x.value;
var c;
function a(){ //添加判断
if(y.value=="nan"){
c="先生"
}
else if(y.value=="nv"){
c="女士"
}
document.write("亲爱的"+b+c+"，您好！")
}
function d(){
x.value=""
}
</script>
