javascript SocialHistory 检查访问者是否访问过某站点
作者：
今天delicious上这个名为 SocialHistory 的脚本十分引人注目。源代码可以在这里下载。这段js代码的功能就是判断你的用户有没有访问过某个网站。使用方法很简单，例如：
| window.onload = function() { var sl = new SocialHistory(); alert(sl.doesVisit("www.jb51.net")); } 如果用户曾经使用过www.jb51.net，那么该函数就会返回真，否则返回假。 其实原理并不复杂，它利用了链接的 a:visited 伪类的属性。首先在页面上生成一个iframe，并在这个iframe中设置 a 和 a:visited 为不同的样式。然后将网站的链接插入到 iframe 中。浏览器就会根据用户的访问历史，为访问过的链接设置 a:visited 的样式。最后再获得链接的最终样式，如果是 a:visited，就可以认为用户访问过该网站了。具体的实现方式可以参考源代码。 这个脚本主要用于显示社会性书签的图标，可以恰到好处地显示用户所使用的网站。但我担心，这样的做法是不是有盗取用户隐私之嫌？虽然这个方法只能判断用户有无访问特定的网站，并不能无限制地得到所有访问历史。 /* |
| * Social Limit - Only the social you care about. |
| * |
| * Enables your site to know which social bookmarking badges to display to your |
| * visitors. It tells you all social sites the user has gone to, or you can |
| * query for a specific one. |
| * |
| * For example: |
| * |
| * var sl = SocialHistory(); |
| * alert( sl.doesVisit("Digg") ); // Returns true/false, -1 if unknown. |
| * var listOfVisitedSites = sl.visitedSites(); |
| * var checkedSites = sl.checkedSites(); |
| * |
| * If you want to add more sites to check, you can pass that in as a dictionary |
| * to History: |
| * |
| * var more = { "Humanized": "http://humanized.com", |
| * "Azarask.in": ["http://azarask.in", "http://azarask.in/blog"] |
| * }; |
| * var sl = SocialHistory(more); |
| * alert( sl.doesVisit("Humanized") ); |
| * |
| * For a list of built-in sites, see the sites variable below. |
| * |
| * Copyright (c) 2008 Aza Raskin (http://azarask.in/blog) |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| * |
| */ |
| var SocialHistory = function( moreSites ){ |
| var sites = { |
| "Digg": ["http://digg.com", "http://digg.com/login"], |
| "Reddit": ["http://reddit.com", "http://reddit.com/new/", "http://reddit.com/controversial/", "http://reddit.com/top/", "http://reddit.com/r/reddit.com/", "http://reddit.com/r/programming/"], |
| "StumbleUpon": ["http://stumbleupon.com"], |
| "Yahoo Buzz": ["http://buzz.yahoo.com"], |
| "Facebook": ["http://facebook.com/home.php", "http://facebook.com", "https://login.facebook.com/login.php"], |
| "Del.icio.us": ["https://secure.del.icio.us/login", "http://del.icio.us/"], |
| "MySpace": ["http://www.myspace.com/"], |
| "Technorati": ["http://www.technorati.com"], |
| "Newsvine": ["https://www.newsvine.com", "https://www.newsvine.com/_tools/user/login"], |
| "Songza": ["http://songza.com"], |
| "Slashdot": ["http://slashdot.org/"], |
| "Ma.gnolia": ["http://ma.gnolia.com/"], |
| "Blinklist": ["http://www.blinklist.com"], |
| "Furl": ["http://furl.net", "http://furl.net/members/login"], |
| "Mister Wong": ["http://www.mister-wong.com"], |
| "Current": ["http://current.com", "http://current.com/login.html"], |
| "Menaeme": ["http://meneame.net", "http://meneame.net/login.php"], |
| "Oknotizie": ["http://oknotizie.alice.it", "http://oknotizie.alice.it/login.html.php"], |
| "Diigo": ["http://www.diigo.com/", "https://secure.diigo.com/sign-in"], |
| "Funp": ["http://funp.com", "http://funp.com/account/loginpage.php"], |
| "Blogmarks": ["http://blogmarks.net"], |
| "Yahoo Bookmarks": ["http://bookmarks.yahoo.com"], |
| "Xanga": ["http://xanga.com"], |
| "Blogger": ["http://blogger.com"], |
| "Last.fm": ["http://www.last.fm/", "https://www.last.fm/login/"], |
| "N4G": ["http://www.n4g.com"], |
| "Faves": ["http://faves.com", "http://faves.com/home", "https://secure.faves.com/signIn"], |
| "Simpy": ["http://www.simpy.com", "http://www.simpy.com/login"], |
| "Yigg": ["http://www.yigg.de"], |
| "Kirtsy": ["http://www.kirtsy.com", "http://www.kirtsy.com/login.php"], |
| "Fark": ["http://www.fark.com", "http://cgi.fark.com/cgi/fark/users.pl?self=1"], |
| "Mixx": ["https://www.mixx.com/login/dual", "http://www.mixx.com"], |
| "Google Bookmarks": ["http://www.google.com/bookmarks", "http://www.google.com/ig/add?moduleurl=bookmarks.xml&hl=en"], |
| "Subbmitt": ["http://subbmitt.com/"] |
| }; |
| for( var site in moreSites ) { |
| // If we don't have the site, create the URL list. |
| if( typeof( sites[site] ) == "undefined" ) sites[site] = []; |
| // If the value is string, just push that onto the URL list. |
| if( typeof( moreSites[site] ) == "string" ) |
| sites[site].push( moreSites[site] ); |
| else |
| sites[site] = sites[site].concat( moreSites[site] ); |
| } |
| var visited = {}; |
| function getStyle(el, scopeDoc,styleProp) { |
| if (el.currentStyle) |
| var y = el.currentStyle[styleProp]; |
| else if (window.getComputedStyle) |
| var y = scopeDoc.defaultView.getComputedStyle(el,null).getPropertyValue(styleProp); |
| return y; |
| } |
| function remove( el ) { |
| el.parentNode.removeChild( el ); |
| } |
| // Code inspired by: |
| // bindzus.wordpress.com/2007/12/24/adding-dynamic-contents-to-iframes |
| function createIframe() { |
| var iframe = document.createElement("iframe"); |
| iframe.style.position = "absolute"; |
| iframe.style.visibility = "hidden"; |
| document.body.appendChild(iframe); |
| // Firefox, Opera |
| if(iframe.contentDocument) iframe.doc = iframe.contentDocument; |
| // Internet Explorer |
| else if(iframe.contentWindow) iframe.doc = iframe.contentWindow.document; |
| // Magic: Force creation of the body (which is null by default in IE). |
| // Also force the styles of visited/not-visted links. |
| iframe.doc.open(); |
| iframe.doc.write('<style>'); |
| iframe.doc.write("a{color: #000000; display:none;}"); |
| iframe.doc.write("a:visited {color: #FF0000; display:inline;}"); |
| iframe.doc.write('</style>'); |
| iframe.doc.close(); |
| // Return the iframe: iframe.doc contains the iframe. |
| return iframe; |
| } |
| var iframe = createIframe(); |
| function embedLinkInIframe( href, text ) { |
| var a = iframe.doc.createElement("a"); |
| a.href = href; |
| a.innerHTML = site; |
| iframe.doc.body.appendChild( a ); |
| } |
| for( var site in sites ) { |
| var urls = sites[site]; |
| for( var i=0; i<urls.length; i++ ) { |
| // You have to create elements in the scope of the iframe for IE. |
| embedLinkInIframe( urls[i], site ); |
| // Automatically try variations of the URLS with and without the "www" |
| if( urls[i].match(/www\./) ){ |
| var sansWWW = urls[i].replace(/www\./, ""); |
| embedLinkInIframe( sansWWW, site ); |
| } else { |
| // 2 = 1 for length of string + 1 for slice offset |
| var httpLen = urls[i].indexOf("//") + 2; |
| var withWWW = urls[i].substring(0, httpLen ) + "www." + urls[i].substring( httpLen ); |
| embedLinkInIframe( withWWW, site ); |
| } |
| } |
| } |
| var links = iframe.doc.body.childNodes; |
| for( var i=0; i<links.length; i++) { |
| // Handle both Firefox/Safari, and IE (respectively) |
| var displayValue = getStyle(links[i], iframe.doc, "display"); |
| var didVisit = displayValue != "none"; |
| if( didVisit ){ |
| visited[ links[i].innerHTML ] = true; |
| } |
| } |
| remove( iframe ); |
| return new (function(){ |
| var usedSites = []; |
| for( var site in visited ){ |
| usedSites.push( site ); |
| } |
| // Return an array of visited sites. |
| this.visitedSites = function() { |
| return usedSites; |
| } |
| // Return true/false. If we didn't check the site, return -1. |
| this.doesVisit = function( site ) { |
| if( typeof( sites[site] ) == "undefined" ) |
| return -1; |
| return typeof( visited[site] ) != "undefined"; |
| } |
| var checkedSites = []; |
| for( var site in sites ){ |
| checkedSites.push( site ); |
| } |
| // Return a list of the sites checked. |
| this.checkedSites = function(){ |
| return checkedSites; |
| } |
| })(); |
| } |