对Google Maps API的JS文件解析(map.js)

我下载了Google Maps API所调用的JS文件的源文件，研究了一下，做了一点注释，现在放在下面

var _mSiteName = 'Google Maps';
2

var _mZoomIn = 'Zoom In';
3

var _mZoomOut = 'Zoom Out';
4

var _mZoomSet = 'Click to set zoom level';
5

var _mZoomDrag = 'Drag to zoom';
6

var _mPanWest = 'Go left';
7

var _mPanEast = 'Go right';
8

var _mPanNorth = 'Go up';
9

var _mPanSouth = 'Go down';
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var _mLastResult = 'Return to the last result';
11

var _mGoogleCopy = '?2005 Google';
12

var _mDataCopy = 'Map data ?2005 ';
13

var _mNavteq = 'NAVTEQ?';
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var _mTeleAtlas = 'Tele Atlas';
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var _mZenrin = 'ZENRIN';
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var _mZenrinCopy = 'Map ?2005 ';
17

var _mNormalMap = 'Map';
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var _mNormalMapShort = 'Map';
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var _mHybridMap = 'Hybrid';
20

var _mHybridMapShort = 'Hyb';
21

var _mNew = 'New!';
22

var _mTerms = 'Terms of Use';
23

var _mKeyholeMap = 'Satellite';
24

var _mKeyholeMapShort = 'Sat';
25

var _mKeyholeCopy = 'Imagery ?2005 ';
26

var _mScale = 'Scale at the center of the map';
27

var _mKilometers = 'km';
28

var _mMiles = 'mi';
29

var _mMeters = 'm';
30

var _mFeet = 'ft';
31

var _mDecimalPoint = '.';
32

var _mThousandsSeparator = ',';
33

var _mMapErrorTile = 'We are sorry, but we don\'t have maps at this zoom level for this region.Try zooming out for a broader look.';
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var _mKeyholeErrorTile = 'We are sorry, but we don\'t have imagery at this zoom level for this region.Try zooming out for a broader look.';
35

var _mTermsURL = 'http://www.google.com/help/terms_local.html';
36

var _apiHash = '5f87579ff86792cf982d095a4228e3de6cdaf562';
37

var _apiKey = 'ABQIAAAA7nPTPXCvzWYxyKdmbFQfTxRfh1ef-GeSz5gtCVpCKOPebNr1YhR23M_jRfeqAugNMsW3pZQJAwfCFw';
38

var _mApiBadKey = 'The Google Maps API key used on this web site was registered for a different web site. You can generate a new key for this web site at http://www.google.com/apis/maps/.';
39

function createMapSpecs()
40

{
41

var mt = '';
42

var tv = 'w2.5';
43

var apitv = 'w2.5';
44

var hmt = '';
45

var htv = 'w2t.1';
46

var apihtv = 'w2t.1';
47

var kmt = '';
48

var kdomain = 'google.com';
49

var ktv = '3';
50

var kdisable = false;
51

var khauth = 'fzwq2uohc9nRek9eHfZgC_oFXnYU9GSk3iYwgw';
52

var kjapandatumhack = true;
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var hybrid = (htv != '');
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if (!arguments.callee.mapSpecs)
55

{
56

var mapSpecs = [];
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var tileVersion = window._apiKey ? apitv : tv;
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var hTileVersion = window._apiKey ? apihtv : htv;
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var mapCopy = (tileVersion != tv) ? G_MAP_API_COPYRIGHTS :G_MAP_DEFAULT_COPYRIGHTS;
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var hybridCopy = (hTileVersion != htv) ? G_MAP_API_COPYRIGHTS :G_MAP_DEFAULT_COPYRIGHTS;
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_GOOGLE_MAP_TYPE = new _GoogleMapMercSpec(mt, tileVersion, mapCopy);
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mapSpecs.push(_GOOGLE_MAP_TYPE);
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if (!kdisable)
64

{
65

_SATELLITE_TYPE = new _KeyholeMapMercSpec(kmt, kdomain, ktv, khauth,kjapandatumhack);
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mapSpecs.push(_SATELLITE_TYPE);
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if (hybrid)
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{
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_HYBRID_TYPE = new _HybridMapSpec(kmt, kdomain, ktv, khauth,kjapandatumhack, hmt, hTileVersion,hybridCopy);
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mapSpecs.push(_HYBRID_TYPE);
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}
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_KATRINA_TYPE = new _KatrinaMapSpec(kmt, kdomain, ktv, khauth);
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mapSpecs.push(_KATRINA_TYPE);
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}
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arguments.callee.mapSpecs = mapSpecs;
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}
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return arguments.callee.mapSpecs;
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}
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//取得浏览器名称字符串
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var _u = navigator.userAgent.toLowerCase();
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//检查是否存在t子字符串
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function _ua(t)
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{
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return _u.indexOf(t) != -1;
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}
86

//用t作前缀解析_u，取得_u后面的城市
87

function _uan(t)
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{
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if(!window.RegExp)
90

{
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return 0;
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}
93

var r = new RegExp(t+'([0-9]*)');
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var s = r.exec(_u);
95

var ret = 0;
96

if (s.length >= 2)
97

{
98

ret = s[1];
99

}
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return ret;
101

}
102

//是否支持ActiveX（使用Microsoft.XMLDOM）
103

function _noActiveX()
104

{
105

if(!_ua('msie') || !document.all || _ua('opera'))
106

{
107

return false;
108

}
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var s = false;
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eval('try { new ActiveXObject("Microsoft.XMLDOM"); }'+'catch (e) { s = true; }');
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return s;
112

}
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//检查浏览器名称是否正常
114

function _compat()
115

{
116

return ((_ua('opera') &&(_ua('opera 7.5') || _ua('opera/7.5') ||_ua('opera 8') || _ua('opera/8'))) ||(_ua('safari') && _uan('safari/') >= 125) ||(_ua('msie') &&!_ua('msie 4') && !_ua('msie 5.0') && !_ua('msie 5.1') &&!_ua('msie 3') && !_ua('powerpc')) ||(document.getElementById && window.XSLTProcessor &&window.XMLHttpRequest && !_ua('netscape6') &&!_ua('netscape/7.0')));
117

}
118

//这里也比较让人费解，_compat和_browserIsCompatible、GBrowserIsCompatible其实都差不多啊
119

_fc = false;
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_c = _fc || _compat();
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//返回浏览器兼容性，不知道为什么会有两个一样的函数
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function _browserIsCompatible()
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{
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return _c;
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}
126

function GBrowserIsCompatible()
127

{
128

return _c;
129

}
130

//判断浏览器是否存在xslt解析
131

function _havexslt()
132

{
133

if (typeof GetObject != 'undefined' ||(typeof XMLHttpRequest != 'undefined' &&typeof DOMParser != 'undefined' &&typeof XSLTProcessor != 'undefined'))
134

{
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return true;
136

}
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else
138

{
139

return false;
140

}
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}
142

//载入一个JS文件
143

function _script(src)
144

{
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var ret='<'+'script src="'+src+'"'+' type="text/javascript"><'+'/script>';
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document.write(ret);
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}
148

//根据浏览器兼容性情况加载不同的JS文件
149

function _loadMapsScript()
150

{
151

if(_havexslt())
152

{
153

_script("http://maps.google.com/mapfiles/maps.21.js");
154

}
155

else if(_ua('safari'))
156

{
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_script("http://maps.google.com/mapfiles/maps.21.safari.js");
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}
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else
160

{
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_script("http://maps.google.com/mapfiles/maps.21.xslt.js");
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}
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}
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//如果浏览器兼容并支持ActiveX，则加载JS文件
165

if (_c && !_noActiveX())
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{
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document.write('');
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document.write('');
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_loadMapsScript();
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}
171

很明显，其实这些只是一些基本的浏览器检测函数，而最重要的内容都在第149行的函数_loadMapsScript加载的函数文件里面，而这几个文件都特别大，我正准备以后进行分析。

posted on 2005-09-30 17:45 K_Reverter 阅读(3009) 评论(0) 编辑收藏举报

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对Google Maps API的JS文件解析(map.js)