Ajax 返回三种值 解例

Ajax中的x指的是xml，早期的数据格式都喜欢用XML，然后一层层的解析。当然简单的也会返回HTML(或称HTML片段)。
现在使用JSON格式的也很多。根据不同需求，给Ajax对象添加了三个实用方法：Ajax.text、Ajax.json、Ajax.xml。

Ajax.text返回纯文本，即responseText

Ajax.json返回json，即会将responseText解析成js对象

Ajax.xml返回xml文档，即responseXML

使用方式与Ajax.request相同，第一个参数是请求url，第二个是配置参数。

完整代码

view sourcePRint?

01Ajax = 

02function(){

03    function request(url,opt){

04        function fn(){}

05        var async   = opt.async !== false,

06            method  = opt.method    || 'GET',

07            type    = opt.type      || 'text',

08            encode  = opt.encode    || 'UTF-8',

09            data    = opt.data      || null,

10            success = opt.success   || fn,

11            failure = opt.failure   || fn;

12            method  = method.toUpperCase();

13        if(data && typeof data == 'object'){//对象转换成字符串键值对

14            data = _serialize(data);

15        }

16        if(method == 'GET' && data){

17            url += (url.indexOf('?') == -1 ? '?' : '&') + data;

18            data = null;

19        }   

20        var xhr = window.xmlhttpRequest ? new XMLHttpRequest() : newActiveXObject('Microsoft.XMLHTTP');

21        xhr.onreadystatechange = function(){

22            _onStateChange(xhr,type,success,failure);

23        };

24        xhr.open(method,url,async);

25        if(method == 'POST'){

26            xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded;charset='+ encode);

27        }

28        xhr.send(data);

29        return xhr; 

30    }

31    function _serialize(obj){

32        var a = [];

33        for(var k in obj){

34            var val = obj[k];

35            if(val.constructor == Array){

36                for(var i=0,len=val.length;i<len;i++){

37                    a.push(k + '=' + encodeURIComponent(val[i]));

38                }               

39            }else{

40                a.push(k + '=' + encodeURIComponent(val));

41            }               

42        }

43        return a.join('&');

44    }

45    function _onStateChange(xhr,type,success,failure){

46        if(xhr.readyState == 4){

47            var s = xhr.status, result;

48            if(s>= 200 && s < 300){

49                switch(type){

50                    case 'text':

51                        result = xhr.responseText;

52                        break;

53                    case 'json':

54                        result = function(str){

55                            return (new Function('return ' + str))();

56                        }(xhr.responseText);

57                        break;

58                    case 'xml':

59                        result = xhr.responseXML;

60                        break;

61                }

62                success(result);    

63            }else{

64                failure(xhr);

65            }

66        }else{}

67    }

68    return (function(){

69        var Ajax = {request:request}, types = ['text','json','xml'];

70        for(var i=0,len=types.length;i<len;i++){

71            Ajax[types[i]] = function(i){

72                return function(url,opt){

73                    opt = opt || {};

74                    opt.type = types[i];

75                    return request(url,opt);

76                };

77            }(i);

78        }

79        return Ajax;

80    })();

81}();