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relatedLinks()
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s+='<img src="'+urlStt+'images/style/home.svg" style="height:'+ht+'px; vertical-align:middle;" alt="Home" />'
s+='</a>'
s+='</li>'
s+='<li><a role="listitem" href="#">Subjects &#x25BC;</a>'
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s+='<img src="'+urlStt+'images/style/search.svg" style="height:'+ht+'px; vertical-align:middle;" alt="Search" />'
s+='</a>'
s+='</li>'
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function themeChgHTML(){let s=''
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div.style.position='relative'}else{div.style.display='block'
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s+='<script type="text/javascript">'
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function cookMsg(){let s=''
let imgHome=(document.domain=='localhost'?'/mathsisfun':'')+'/'
s+='We may use <a href="'+imgHome+'about-ads.html">Cookies</a> &nbsp;'
s+='<div class="btn" style="display:inline-block; cursor: pointer;" onclick="cookOK()">OK</div>'
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function cookOK(){console.log('cookOK')
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let script=document.createElement('script')
script.type='text/javascript'
script.setAttribute('async','async')
script.src='../pagead2.googlesyndication.com/pagead/js/f.txt'
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let ins=document.createElement('ins')
ins.setAttribute('class','adsbygoogle')
ins.setAttribute('style','display:block;')
ins.setAttribute('data-ad-client','ca-pub-1389989178296449')
ins.setAttribute('data-ad-slot','2009442555')
ins.setAttribute('data-ad-format','auto')
ins.setAttribute('data-full-width-responsive','true')
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dest.appendChild(ins)
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inlineScript.type='text/javascript'
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dest.appendChild(inlineScript)
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path=path.split('mathsisfun/index.html').join('index.html')
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let file=path.substring(path.lastIndexOf('index.html')+1)
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path=path.split('mathsisfun/index.html').join('index.html')
let src=''
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let s=adCodeGet(src)
return s}
function adCodeGet(src){let s=''
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function linksHTML(){let url=location.href
let urlenc=encodeURIComponent(location.href)
let title=encodeURIComponent(document.title)
let linkstt='<a target="_blank"  rel="noopener nofollow" href="'
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s+='<a href="javascript:linkToUs()" id="linkus" title="Link To Us"></a>'
s+=linkstt+'https://www.facebook.com/sharer/sharer.php?u='+url+'&t='+title+'" title="Share on Facebook" id="linkfb"></a> '
s+=linkstt+'https://twitter.com/intent/tweet?source='+url+'&text='+title+':%20'+url+'" title="Tweet it" id="linktw"></a> '
s+=linkstt+'http://pinterest.com/pin/create/button/?url='+url+'&description='+title+'" title="Pin it" id="linkpi"></a>'
s+='<a href="javascript:tellAFriend()" id="linkem" title="eMail a Friend"></a>'
return s}
function footerHTML(){let s=''
let urlStt=urlSttGet()
let sep=' &cir; '
s+='<div id="footMenu">'
s+='<a href="'+urlStt+'search/search.html">Search</a>'+sep
s+='<a href="'+urlStt+'links/index.html">Index</a>'+sep
s+='<a href="'+urlStt+'aboutmathsisfun.html">About</a>'+sep
s+='<a href="'+urlStt+'contact.php">Contact</a>'+sep
s+='<a href="javascript:citation()">Cite&nbsp;This&nbsp;Page</a>'+sep
s+='<b><a href="'+urlStt+'Privacy.htm">Privacy</a></b>'
s+='</div>'
return s}
function footer2HTML(){let urlStt=urlSttGet()
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let s=''
s+='<div class="foot">'
for(let i=0;i<links.length;i++){let link=links[i]
if(link[2]==1){if(i>0)s+='</div>'
s+='<div class="footCol">'
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s+='</div>\n'}}
s+='<br><a href="javascript:citation()">Cite This Page</a>'
s+='</div>'
console.log('foot',s)
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function themeChg(){let was=themeGet()
let theme=was=='lite'?'dark':'lite'
themeSet(theme)
document.getElementById('themeSlider').checked=theme=='dark'}
function themeGet(){let theme=localStorage.getItem('theme')
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if(theme!='lite'&&theme!='dark'){theme='lite'
localStorage.setItem('theme',theme)}
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function themeSet(theme){localStorage.setItem('theme',theme)
console.log('themeSet',theme,document.documentElement.hasAttribute('theme'))
document.documentElement.setAttribute('theme',theme)}
function adsHideHTML(){let s=''
s+='<div id="adsShow1"><a href="javascript:adsShow()">Show Ads</a></div>'
s+='<div id="adsHide1"><a href="javascript:adsHide()">Hide Ads</a> | '
let imgHome=(document.domain=='localhost'?'/mathsisfun':'')+'/'
s+='<a href="'+imgHome+'about-ads.html">About Ads</a> </div>'
return s}
function adsHideSet(){if(adOffQ()){adsSet(false)}}
function gTagHTML(){let s=''
s+='<script async src="https://www.googletagmanager.com/gtag/js?id=UA-29771508-1"></script>'
s+='<script>'
s+='window.dataLayer = window.dataLayer || [];'
s+='function gtag(){dataLayer.push(arguments);}'
s+="gtag('js', new Date());"
s+="gtag('config', 'UA-29771508-1');"
s+='</script>'
return s}
function logVisit(){let pg=location.pathname
if(pg=='index.html')return
let pgHex=toHex(pg)
addVisit(pgHex,'visit',window.location.hostname)}
if(Math.random()<0.1)logVisit()
function addVisit(pg,viewtype,hostname){console.log('addVisit',viewtype,hostname)
let req
req=new XMLHttpRequest()
let params='type='+viewtype
params+='&site=mif'
params+='&pg='+encodeURIComponent(pg)
params+='&lang='+encodeURIComponent(window.navigator.language)
params+='&ref='+encodeURIComponent(toHex(document.referrer))
req.open('POST.html','https://mi2f.com/update.php',true)
req.setRequestHeader('Content-type','application/x-www-form-urlencoded')
req.send(params)}
function onScroll(){let scrollTop=document.documentElement?document.documentElement.scrollTop:document.body.scrollTop
let menu=document.getElementById('menu')
if(scrollTop>100){menu.style.top='0px'
menu.style.width='1000px'
menu.style.border='1px solid #ffffff'
menu.style.boxShadow='0px 12px 12px -12px #77cc77'
menu.style.backgroundColor='white'
menu.style.textAlign='center'
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menu.style.zIndex='5000'}else{menu.style.boxShadow='none'
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function relatedLinks(){if(window.innerWidth<860){return}
let rels=document.getElementsByClassName('related')
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let links=rel.getElementsByTagName('a')
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let left=null
if(count==1)right=links[0]
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right=links[1]}
let s=''
let top=220
if(left!=null){s+='<div style="position: absolute; top: '+top+'px; left: 0px; text-align: left; z-index:2;">'
s+=fmtMenuBox(left.href,left.text,0)
s+='</div>'}
if(right!=null){s+='<div style="position: absolute; top: '+top+'px; right: 0px; text-align: right; z-index:2;">'
s+=fmtMenuBox(right.href,right.text,1)
s+='</div>'}
document.getElementById('stt').innerHTML+=s}
function fmtMenuBox(url,txt,dirn){let s=''
let boxID=dirn==0?'menuLt':'menuRt'
s+='<a href="'+url+'"  style="text-decoration: none; color: #8ac; line-height:1.3rem; ">'
s+='<div id="'+boxID+'">'
s+=txt
s+='</div>'
s+='</a>'
return s}
function vidDo(id,spanid){let s=''
let visIndex=videoVis.indexOf(spanid)
let visQ=visIndex>-1?true:false
if(visQ){let frame=document.getElementById(spanid+'v1')
frame.parentNode.removeChild(frame)
videoVis.splice(visIndex,1)
visQ=false}else{s+='<div style="width:100vw;"></div>'
s+='<iframe id="'+spanid+'v1" src="https://www.youtube.com/embed/'+id+'?rel=0&autoplay=1" frameborder="0" allowfullscreen style=" vertical-align:top; "></iframe>'
s+='<div style="width:100vw;"></div>'
videoVis.push(spanid)
visQ=true}
let vid=document.getElementById(spanid)
vid.innerHTML=s
vid.style.border='5px solid blue;'
console.log('vidDo',vid)
if(visQ)resizeVideo(spanid)}
function resizeVideo(spanid){let v1=document.getElementById(spanid+'v1')
let wd=window.innerWidth-40
if(wd>640)wd=640
v1.style.width=wd+'px'
v1.style.height=wd*(340/640)+80+'px'}
let videoVis=[]
function mainDo(){if(document.getElementById('menuWide')==null)return
document.getElementById('menuWide').innerHTML=menuHTML(0)
document.getElementById('menuSlim').innerHTML=menuHTML(1)
document.getElementById('menuTiny').innerHTML=menuHTML(2)
document.getElementById('adHide').innerHTML=adsHideHTML()
if(localStorage.getItem('cookie')=='ok'){}else{document.getElementById('cookOK').innerHTML=cookMsg()}
document.getElementById('search').innerHTML=searchHTML()
document.getElementById('linkto').innerHTML=linksHTML()
document.getElementById('logo').innerHTML+=themeChgHTML()
document.getElementById('themeSlider').checked=themeGet()=='dark'
document.getElementById('footer').innerHTML=footerHTML()
let qDivs=document.querySelectorAll('.questions')
for(let i=0;i<qDivs.length;i++){qsExpand(qDivs[i])}
let vidDivs=document.querySelectorAll('.video')
for(let i=0;i<vidDivs.length;i++){vidExpand(vidDivs[i],i)}
let scriptDivs=document.querySelectorAll('.script')
for(let i=0;i<scriptDivs.length;i++){scriptExpand(scriptDivs[i])}
if(document.domain=='localhost'){let dummy=document.createElement('img')
dummy.setAttribute('src','mathsisfun/images/style/320x60.html')
dummy.setAttribute('alt','dummy image')
dummy.setAttribute('width','320')
dummy.setAttribute('height','60')
let dest=document.getElementById('adend')
dest.appendChild(dummy)}else{setTimeout(adsenseDo,1000)}
adsHideSet()
doLocal()
document.getElementById('searchFld').addEventListener('keyup',searchKey)}
function searchHTML(){let s=''
s+='<form autocomplete="off" action="'+urlSttGet()+'search/search.html" method="get">'
s+='<input type="text" id="searchFld" name="query" value="" placeholder="Search" aria-label="Search" />'
s+='<input type="submit" id="searchBtn" name="submit" value="" aria-label="Search Button" />'
s+='<input type="hidden" name="search" value="1" />'
s+='</form>'
return s}
function searchKey(ev){let val=ev.target.value
console.log('searchKey',val)
if(main.searchScript=='no'){main.searchScript='loading'
let script=document.createElement('script')
script.onload=function(){console.log('Script loaded and ready')
searchDo(ev)
main.searchScript='yes'}
let imgHome=(document.domain=='localhost'?'/mathsisfun':'')+'/search/images/'
script.src=imgHome+'search-lib.js'
document.getElementsByTagName('head')[0].appendChild(script)}
if(main.searchScript=='yes')searchDo(ev)
return}
function qsExpand(node){let str=node.innerHTML
if(str.includes('getQ('))return
console.log('qsExpand',str)
let newStr=qsHTML(str)
node.innerHTML=newStr}
function qsHTML(qStr){let qs=qStr.trim().split(/[^0-9]+/)
let joinedStr=qs.join('_')
let s=''
for(let i=0;i<qs.length;i++){s+='<a href="javascript:doQ('+qs[i]+",'"+joinedStr+"'"+')">Question&nbsp;'+(i+1)+'</a> '}
return s}
function vidExpand(div,n){let str=div.innerHTML
if(str.trim().length<=1)return
let newStr=vidHTML(str,'title','video'+n)
div.innerHTML=newStr}
function vidHTML(id,titleid='title',spanid='video',style='span'){id=id.replace(/&minus;/g,'-')
let s=''
switch(style){case 'span':s+='<a href="javascript:vidDo(\''+id+"','"+spanid+'\')">'
s+='<img src="'+urlSttGet()+'images/style/video.svg" alt="Video" style="width:70px; height:37px;vertical-align:middle; border:none;" />'
s+='</a>'
s+='<span id="'+spanid+'" style=""></span>'
break
case 'h1':let title=document.getElementById(titleid).innerHTML
s+='<div class="centerfull" style="clear:both; font-weight:400; padding: 0;">'
s+='<div style="float:left; width:60px; text-align:left;">'
s+='  <a href="javascript:vidDo(\''+id+"','"+spanid+'\')">'
s+='    <img src="'+urlSttGet()+'images/style/video.svg" alt="Video" height="32" style="vertical-align:middle; border:none;" />'
s+=' </a>'
s+='</div>'
s+='<div style="float:right; width:60px; text-align:right;">&nbsp;</div>'
s+='  <div style="margin:0 auto;">'
s+='    <h1>'+title+'</h1>'
s+='  </div>'
s+='</div>'
break
case 'h2':title=document.getElementById(titleid).innerHTML
s+='<div style="float:right; width:100px; margin: -10px 0 5px 0;">'
s+='  <a href="javascript:vidDo(\''+id+"','"+spanid+'\')">'
s+='    <img src="'+urlSttGet()+'images/style/video.svg" alt="Video" height="32" style="vertical-align:middle; border:none;" />'
s+=' </a>'
s+='</div>'
s+='    <h2>'+title+'</h2>'
break}
return s}
function initVideo(id,titleid,spanid,style){titleid=typeof titleid!=='undefined'?titleid:'title'
spanid=typeof spanid!=='undefined'?spanid:'video'
style=typeof style!=='undefined'?style:'h1'
document.getElementById(titleid).innerHTML=vidHTML(id,titleid,spanid,style)}
function scriptExpand(node){let str=node.innerHTML
if(str.trim().length<=1)return
iframeDo(node,str)}
function putFlash6(w,h,swf,querystring,clr,noflash){}
function putFlash7(w,h,swf,querystring,clr,noflash){console.log('putFlash7: '+swf)
let s='<div id="container"></div>'
document.write(s)
window.RufflePlayer=window.RufflePlayer||{}
window.addEventListener('load',(event)=>{const ruffle=window.RufflePlayer.newest()
const player=ruffle.createPlayer()
const container=document.getElementById('container')
container.appendChild(player)
player.load(swf)})}
function putFlash8(w,h,swf,querystring,clr,noflash){console.log('putFlash8: '+swf)
window.RufflePlayer=window.RufflePlayer||{}
window.addEventListener('load',(event)=>{const ruffle=window.RufflePlayer.newest()
const player=ruffle.createPlayer()
const container=document.getElementById('container')
console.log('container',container)
container.appendChild(player)
player.load(swf)})}
function iframeDo(node,fileStr){let fileNames=fileStr.split(',')
let filename=fileNames[fileNames.length-1].trim()
let imgHome=document.domain=='localhost'?'/mathsisfun/':'/'
let sttWd=parseInt(node.getBoundingClientRect().width)
let sttHt=parseInt(node.getBoundingClientRect().height)
let aspect=parseFloat(node.style.gap)
let maxQ=!isNaN(aspect)
console.log('iframe',node,node.style.gap,aspect,maxQ)
let htQ=node.style.height.length>0
let iframe=document.createElement('iframe')
if(htQ){iframe.width=sttWd
iframe.height=sttHt}else{iframe.height='200'}
iframe.style=`display:block; margin:auto; border:none; background-color:transparent; overflow:hidden;
  transition:all 0.6s ease-in-out;`
iframe.scrolling='no'
iframe.setAttribute('title','JavaScript Animation')
console.log('iframe',filename,sttWd,sttHt,htQ,maxQ)
let html='<!doctype html><html><head>'
html+='<meta http-equiv="content-type" content="text/html; charset=utf-8" />'
for(let i=0;i<fileNames.length-1;i++){html+='<script src="'+imgHome+fileNames[i].trim()+'"></script>'}
html+='<link rel="stylesheet" href="'+imgHome+'style4.css">'
html+='<script src="'+imgHome+'iframe.js" defer></script>'
html+='<style>body { background: transparent; }</style>'
html+='</head>'
html+='<body style="text-align:center;">'
html+=`<script defer src="${filename}"></script>`
html+='</body>'
html+='</html>'
node.parentElement.insertBefore(iframe,node)
node.style.display='none'
iframe.contentWindow.document.open()
iframe.contentWindow.document.write(html)
iframe.contentWindow.document.close()
iframe.addEventListener('load',function(){let btnQ=false
let aQ=false
iframe.style.maxWidth='100%'
let bestWd=0,bestHt=0
if(htQ){bestWd=sttWd
bestHt=sttHt}else{bestWd=0
iframe.width=bestWd+'px'
bestHt=iframe.contentDocument.body.scrollHeight+1
iframe.height=bestHt+'px'}
setInterval(function(){if(maxQ){let wd=window.innerWidth
let ht=window.innerHeight-60
let newAspect=wd/ht
if(newAspect>aspect){wd=ht*aspect}else{ht=wd/aspect}
iframe.width=wd+'px'
iframe.height=ht+'px'
return}
let wd,ht
if(false){let div=iframe.contentDocument.body.children[0].children[0]
let rect=div.getBoundingClientRect()
wd=rect.width
ht=rect.height}else{wd=iframe.contentDocument.body.scrollWidth+1
ht=iframe.contentDocument.body.scrollHeight+1}
if(wd!=bestWd){console.log('chg wd',bestWd,'to',wd)
bestWd=wd
if(!aQ){iframe.width='100%'}else{iframe.width=bestWd+'px'
aQ=true}}
if(ht>bestHt||ht<bestHt-10){console.log('chg ht',bestHt,'to',ht)
bestHt=ht
iframe.height=bestHt+'px'}
if(!btnQ){let wd=iframe.contentDocument.body.scrollWidth+40
let ht=iframe.contentDocument.body.scrollHeight+1
let div=iframe.contentDocument.getElementById('resize')
if(div!=null){let btnStr='<button type="button" class="btn" style="z-index:2; position:absolute; right:0; bottom:0;" onclick="iframeMax(\''+filename+"',"+wd+','+ht+')">&rect;</button>'
div.innerHTML=btnStr}
btnQ=true}},650)})}
function rpLog(id){let now=performance.now()
if(main.timeStt==undefined){main.timeStt=performance.now()
main.timePrev=performance.now()}
console.log(''+id+': '+parseInt(now-main.timeStt)+'ms => '+parseInt(now-main.timePrev)+'ms')
main.timePrev=now}
themeSet(themeGet())
window.onload=mainDo