<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>

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
}]