< script type = " text/javascript " src = " http://domain2.com/getjson?jsonp=parseResponse " > < / script>

响应值：parseResponse({

" Name " : " Cheeso " , " Rank " : 7 })

1 页面调用的是getJSON：

2

3 getJSON: function ( url, data, callback ) {

4 return jQuery.get(url, data, callback, " json " );

5 },

6

7

8 继续跟进

9

10 get: function ( url, data, callback, type ) {

11 // shift arguments if data argument was omited

12   if ( jQuery.isFunction( data ) ) {

13 type = type || callback;

14 callback = data;

15 data = null ;

16 }

17

18 return jQuery.ajax({

19 type: " GET " ,

20 url: url,

21 data: data,

22 success: callback,

23 dataType: type

24 });

25

26  

1 // Build temporary JSONP function

2   if ( s.dataType === " json " && (s.data && jsre.test(s.data) || jsre.test(s.url)) ) {

3 jsonp = s.jsonpCallback || ( " jsonp " + jsc ++ );

4

5 // Replace the =? sequence both in the query string and the data

6   if ( s.data ) {

7 s.data = (s.data + "" ).replace(jsre, " = " + jsonp + " $1 " );

8 }

9

10 s.url = s.url.replace(jsre, " = " + jsonp + " $1 " );

11

12 // We need to make sure

13   // that a JSONP style response is executed properly

14   s.dataType = " script " ;

15

16 // Handle JSONP-style loading

17   window[ jsonp ] = window[ jsonp ] || function ( tmp ) {

18 data = tmp;

19 success();

20 complete();

21 // Garbage collect

22   window[ jsonp ] = undefined;

23

24 try {

25 delete window[ jsonp ];

26 } catch (e) {}

27

28 if ( head ) {

29 head.removeChild( script );

30 }

31 };

32 }

33

34 if ( s.dataType === " script " && s.cache === null ) {

35 s.cache = false ;

36 }

37

38 if ( s.cache === false && type === " GET " ) {

39 var ts = now();

40

41 // try replacing _= if it is there

42   var ret = s.url.replace(rts, " $1_= " + ts + " $2 " );

43

44 // if nothing was replaced, add timestamp to the end

45   s.url = ret + ((ret === s.url) ? (rquery.test(s.url) ? " & " : " ? " ) + " _= " + ts : "" );

46 }

47

48 // If data is available, append data to url for get requests

49   if ( s.data && type === " GET " ) {

50 s.url += (rquery.test(s.url) ? " & " : " ? " ) + s.data;

51 }

52

53 // Watch for a new set of requests

54   if ( s.global && ! jQuery.active ++ ) {

55 jQuery.event.trigger( " ajaxStart " );

56 }

57

58 // Matches an absolute URL, and saves the domain

59   var parts = rurl.exec( s.url ),

60 remote = parts && (parts[ 1 ] && parts[ 1 ] !== location.protocol || parts[ 2 ] !== location.host);

61

62 // If we're requesting a remote document

63   // and trying to load JSON or Script with a GET

64   if ( s.dataType === " script " && type === " GET " && remote ) {

65 var head = document.getElementsByTagName( " head " )[ 0 ] || document.documentElement;

66 var script = document.createElement( " script " );

67 script.src = s.url;

68 if ( s.scriptCharset ) {

69 script.charset = s.scriptCharset;

70 }

71

72 // Handle Script loading

73   if ( ! jsonp ) {

74 var done = false ;

75

76 // Attach handlers for all browsers

77   script.onload = script.onreadystatechange = function () {

78 if ( ! done && ( ! this .readyState ||

79 this .readyState === " loaded " || this .readyState === " complete " ) ) {

80 done = true ;

81 success();

82 complete();

83

84 // Handle memory leak in IE

85   script.onload = script.onreadystatechange = null ;

86 if ( head && script.parentNode ) {

87 head.removeChild( script );

88 }

89 }

90 };

91 }

92

93 // Use insertBefore instead of appendChild to circumvent an IE6 bug.

94   // This arises when a base node is used (#2709 and #4378).

95   head.insertBefore( script, head.firstChild );

96

97 // We handle everything using the script element injection

98   return undefined;

99 }

100