$(selector).serialize()

<form id="form1">
   <input name="length" type="text" value="pipi" />
   <input name="blog" type="text" value="blue submarine" />
</form>
//使用:$("#form1").serialize();

$.ajax({
    type: "POST",
    dataType: "json",
    url:ajaxCallBack,
    data:$('#myForm').serialize(),// 要提交表單的ID
    success: function(msg){
        alert(msg);
    }
});

 <script src="jquery-1.7.min。js"></script>
<script>
$(function(){
   $("#submit").click(function(){
     alert($("#myForm").serialize());
   });
});
</script>
<form id="myForm">
昵稱 <input type="text" name="username" value="admin" /><br />
密碼 <input type="password" name="password" value="admin123" /><br />
<input type="button" id="submit" value="序列化表單" />
</form>

username=admin&password=admin123

 param: function( a ) {
        ///    <summary>
        ///        This method is internal.  Use serialize() instead.
        ///    </summary>
        ///    <param name="a" type="Map">A map of key/value pairs to serialize into a string.</param>'
        ///    <returns type="String" />
        ///    <private />
        var s = [ ];
        function add( key, value ){
            s[ s.length ] = encodeURIComponent(key) + '=' + encodeURIComponent(value);
        };
        // If an array was passed in, assume that it is an array
        // of form elements
        if ( jQuery.isArray(a) || a.jquery )
            // Serialize the form elements
            jQuery.each( a, function(){
                add( this.name, this.value );
            });
        // Otherwise, assume that it's an object of key/value pairs
        else
            // Serialize the key/values
            for ( var j in a )
                // If the value is an array then the key names need to be repeated
                if ( jQuery.isArray(a[j]) )
                    jQuery.each( a[j], function(){
                        add( j, this );
                    });
                else
                    add( j, jQuery.isFunction(a[j]) ? a[j]() : a[j] );
        // Return the resulting serialization
        return s.join("&").replace(/%20/g, "+");
    }

var obj = {a:1,b:2,c:3};
var k = $.param(obj);
alert(k);    //輸出a=1&b=2&c=3

serializeArray: function() {
        ///    <summary>
        ///        Serializes all forms and form elements but returns a JSON data structure.
        ///    </summary>
        ///    <returns type="String">A JSON data structure representing the serialized items.</returns>
        return this.map(function(){
            return this.elements ? jQuery.makeArray(this.elements) : this;
        })
        .filter(function(){
            return this.name && !this.disabled &&
                (this.checked || /select|textarea/i.test(this.nodeName) ||
                    /text|hidden|password|search/i.test(this.type));
        })
        .map(function(i, elem){
            var val = jQuery(this).val();
            return val == null ? null :
                jQuery.isArray(val) ?
                    jQuery.map( val, function(val, i){
                        return {name: elem.name, value: val};
                    }) :
                    {name: elem.name, value: val};
        }).get();
    }

[ {   name : username,   value : 中國   }, {   name : password,   value : xxx  }]