forked from wchaowu/javascript
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy path9 - Creating XHR objects with branching.js
More file actions
67 lines (59 loc) · 1.48 KB
/
Copy path9 - Creating XHR objects with branching.js
File metadata and controls
67 lines (59 loc) · 1.48 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
/* SimpleXhrFactory singleton, step 1. */
var SimpleXhrFactory = (function() {
// The three branches.
var standard = {
createXhrObject: function() {
return new XMLHttpRequest();
}
};
var activeXNew = {
createXhrObject: function() {
return new ActiveXObject('Msxml2.XMLHTTP');
}
};
var activeXOld = {
createXhrObject: function() {
return new ActiveXObject('Microsoft.XMLHTTP');
}
};
})();
/* SimpleXhrFactory singleton, step 2. */
var SimpleXhrFactory = (function() {
// The three branches.
var standard = {
createXhrObject: function() {
return new XMLHttpRequest();
}
};
var activeXNew = {
createXhrObject: function() {
return new ActiveXObject('Msxml2.XMLHTTP');
}
};
var activeXOld = {
createXhrObject: function() {
return new ActiveXObject('Microsoft.XMLHTTP');
}
};
// To assign the branch, try each method; return whatever doesn't fail.
var testObject;
try {
testObject = standard.createXhrObject();
return standard; // Return this if no error was thrown.
}
catch(e) {
try {
testObject = activeXNew.createXhrObject();
return activeXNew; // Return this if no error was thrown.
}
catch(e) {
try {
testObject = activeXOld.createXhrObject();
return activeXOld; // Return this if no error was thrown.
}
catch(e) {
throw new Error('No XHR object found in this environment.');
}
}
}
})();