构造AJAX参数， 表单元素JSON相互转换

ajax提交服务器数据， 整理一下转换方法。

HTML：

　　 <form id="fm" name="fm" action="">
        <input name="UserName" type="text" value="UserName1"/>
    </form>
    <input name="UserId" id="UserId" type="text" value="UserId1"/>

1.表单元素转QueryString

var q = $('#fm,#UserId').serialize(); //q = UserName=UserName1&UserId=UserId1

2.字符串， JSON 互相转换

var obj = jQuery.parseJSON('{"name":"John"}');
alert( obj.name === "John" );

可以利用jquery-json插件实现转换，直接引用示例

var thing = {plugin: 'jquery-json', version: 2.3};
var encoded = $.toJSON( thing );
// '{"plugin":"jquery-json","version":2.3}'
var name = $.evalJSON( encoded ).plugin;
// "jquery-json"
var version = $.evalJSON(encoded).version;
// 2.3

3.表单，元素转Name,Value数组

var arr = $("#fm,#UserId").serializeArray();
/*[ 
     {name: 'UserName', value: '"UserName"1'}, 
     {name: 'UserId', value: 'UserId'}
  ] */

4. 表单元素转JSON

$.fn.serializeObject = function()
{
    var o = {};
    var a = this.serializeArray();
    $.each(a, function() {
        if (o[this.name] !== undefined) {
            if (!o[this.name].push) {
                o[this.name] = [o[this.name]];
            }
            o[this.name].push(this.value || '');
        } else {
            o[this.name] = this.value || '';
        }
    });
    return o;
};
var obj = $('form').serializeObject();
/*obj: Object
UserId: "UserId1"
UserName: "UserName1"
__proto__: Object*/

5. JSON2FORM

$.getJSON('url_to_file', function(data) {
    for (var i in data) {
        $('input[name="'+i+'"]').val(data[i]);
    }
}

Google过程中发现一个更强大的插件 http://code.google.com/p/jquery-load-json/

data = {
                    "Name":"Emkay Entertainments",
                    "Address":"Nobel House, Regent Centre",
                    "Contact":"Phone"
        }  
 $('div#data').loadJSON(data);
 
 <div id="data">
            <h1 id="Name">Emkay Entertainments</h1>
            <label for="Address">Address:</label>
            <span id="Address">Nobel House, Regent Centre</span>        
            <label for="Contact">Contact by:</label>
            <span id="Contact">Phone</span>
        </div>

live demo :http://jquery-load-json.googlecode.com/svn/trunk/edit.html?ID=

ajax提交参数是，要注意提交参数的类型。如easyui grid 参数只能用JSON,不支持QueryString