js 阻止form表单提交

<form action="/login.htm" method="post" onsubmit="return updateLocation();">
<input name="input" type="submit" value="提交" />
</form>

<script>
function updateLocation(){
if($("#store_lng").val()){
return true ;
} else {
alert("请在地址列表选择一个地址");
return false ;
}
}
</script>