jQuery Validate插件ajax方式驗證輸入值的實例

<form id="registForm"> 
 <input type="text" id="username" name="username"> 
</form> 

// 導入jquery、validte庫略
$(function() {
	$.validator.setDefaults({
	submitHandler: function(form) {
	// 驗證通過處理
	...
	}
	});
	
	$("#registForm").validate({
	rules: {
	username: {
	required: true,
	remote: "checkUsername.do"
	},	
	},
	messages: {
	username: {
	required: "用戶名不能為空",
	remote: "用戶名已經存在"
	}
	}
	});
});

@RequestMapping("/checkUsername")
public @ResponseBody boolean checkUsername(@RequestParam String username) {
	// 測試
	return !"test".equals(username);
}

@RequestMapping("/checkUsername")
public @ResponseBody String checkUsername(@RequestParam String username) {
	// 測試
	return !"test".equals(username) ? "true" : "false";
}

....
username: {
	required: true,
	remote: {
	url: "checkUsername.do",
	type: "post", //數據發送方式
	dataType: "json", //接受數據格式 
	data: { //要傳遞的數據
	username: function() {
	return $("#username").val();
	},
	extra: function() {
	return "額外信息";
	}
	 }
	}
}

@RequestMapping(value = "/checkUsername", method = RequestMethod.POST)
public @ResponseBody boolean checkUsername(User user, @RequestParam String extra) {
	// 測試
	System.out.println(extra);
	return !"test".equals(user.getUsername());
}