What is autorun.inf ? is autorun.inf virus file?

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function AlexaSiteStatsWidget(){ var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; var jsUrlRegex = /http:\/\/xslt.alexa.com\/site_stats\/js\/(.)\/(.).*(?:[\?&]|&)url=([^\?&]*)/i; var jsAmznIdRegex = /http:\/\/xslt.alexa.com\/site_stats\/js\/.*[\?&]amzn_id=([^\?&]*)/i; var imageSrcPrefix = "http://xsltcache.alexa.com/site_stats/gif/"; var detailURLPrefix = "http://www.alexa.com/data/details/main"; this.replaceScripts = function replaceScripts(){ var scriptElements = document.getElementsByTagName("script"); var thisScript = scriptElements[scriptElements.length - 1]; var scriptSource = thisScript.src; if(scriptSource != null){ var urlMatched = scriptSource.match(jsUrlRegex); var decodedURL = decodeURIComponent(urlMatched[3]); if(urlMatched != null){ var associatedMatched = scriptSource.match(jsAmznIdRegex); var base64EncodedURL = encode64(decodedURL); var imageURL = imageSrcPrefix + urlMatched[1] + "/" + urlMatched[2] + "/" + base64EncodedURL + "/s.gif"; var img = new Image(); var fullURL = getFullURL(decodedURL); img.src = imageURL; img.setAttribute('border', '0'); if(urlMatched[1] == "s") img.alt = "Alexa Certified Traffic Ranking for " + decodedURL; else img.alt = "Alexa Certified Site Stats for " + decodedURL; var newLink=document.createElement('a'); var detailURL = detailURLPrefix; if(associatedMatched != null) detailURL = detailURL + "?amzn_id=" + associatedMatched[1] + "&url=" + fullURL; else detailURL = detailURL + "?url=" + fullURL; newLink.setAttribute('href', detailURL); newLink.className='AlexaSiteStatsWidget'; newLink.appendChild(img); thisScript.parentNode.insertBefore(newLink,thisScript); } } } function getFullURL(inputURL){ if(inputURL.substring(0,5).toLowerCase() != "http:") return "http://" + inputURL; else return inputURL; } function encode64(input) { var output = ""; var chr1, chr2, chr3; var enc1, enc2, enc3, enc4; var i = 0; do { chr1 = input.charCodeAt(i++); chr2 = input.charCodeAt(i++); chr3 = input.charCodeAt(i++); enc1 = chr1 >> 2; enc2 = ((chr1 & 3) << 4) | (chr2 >> 4); enc3 = ((chr2 & 15) << 2) | (chr3 >> 6); enc4 = chr3 & 63; if (isNaN(chr2)) { enc3 = enc4 = 64; } else if (isNaN(chr3)) { enc4 = 64; } output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) + keyStr.charAt(enc4); } while (i < input.length); return output; } } new AlexaSiteStatsWidget().replaceScripts();