1. 異步請求username是否以註冊

1.1 簡單的HTML界面

<div id="registerWindow" class="registerModal">
            <h2>Register</h2>
            <form name="register" id="registerForm" action="" method="post">
                <label class="labelLong" for="penewuser">Please choose a user name: </label><input type="text" name="penewuser" id="penewuser" size="24" /><span class="error">name taken, please choose another</span><br />
                <label class="labelLong" for="penewpass">Please choose a password: </label><input type="password" name="penewpass" id="penewpass" size="24" /><span class="error">password must not be blank</span><br />
                <label class="label" for="pefirstname">First Name: </label><input type="text" name="pefirstname" id="pefirstname" size="16" /><br />
                <label class="label" for="pelastname">Last Name: </label><input type="text" name="pelastname" id="pelastname" size="24" /><br />
                <label class="label" for="email">E-mail: </label><input type="text" name="email" id="email" size="48" /><span class="error">please enter a valid e-mail address</span><br />
                <h3>Photography Interests<span class="modalNote"> (choose all that apply)</span></h3>
                <input type="hidden" name="formName" value="register" />
                <label class="label"> </label><input type="submit" value="Register" /><input type="reset" value="Clear" />
                <p class="modalNote">You can update your interests at any time by modifying settings in "My Account".</p>
            </form>
        </div>

1.2 綁定事件到文本框失去焦點。使用POST方式提交請求。

：參數1設定異步請求的路徑。參數2傳遞了提交的數據，且數據鍵值對中值須要引號。參數3對server返回的數據進行處理。參數4設置server端返回的數據類型。

$(‘#penewuser‘).blur(function() {
	    var newName = $(this).val();
	    $.post(‘inc/peRegister.php‘, {
	        formName: ‘register‘,
	        penewuser: newName
	    }, function(data){
	    	var usernameCount = data;
	    	if(1 == usernameCount){
	    		$(‘#penewuser‘).next(‘.error‘).css(‘display‘, ‘inline‘);
	    	} else {
	    		$(‘#penewuser‘).next(‘.error‘).css(‘display‘, ‘none‘);
	    	}
		}, ‘html‘);
	});

1.3 異步提交FORM表單。

：取消submit的默認操作，然後序列化表單數據。

	$(‘#registerForm‘).submit(function(e) {
		e.preventDefault();
		var formData = $(this).serialize();
		$.post(‘inc/peRegister.php‘, formData, function(data) {	
			var mysqlError = data;
			if(mysqlError > 0){
		        /*
		         *  error deal
		         */
		}, ‘html‘);
	});

：JQuery提供了4中方法通知用戶AJAX狀態。ajaxStart、ajaxSend、ajaxComplete、ajaxStop。ajaxStart會在AJAX請求發出後盡快被調用，該方法能夠綁定到DOM中的不論什麽元素。

ajaxStart會調用模式載入指示器，一旦POST過程完畢後。ajaxStop方法被觸發，導致模式等待指示器淡出。

 $(‘body‘).ajaxStart(function(){
})

JQuery學習(5-AJAX)