//copyright 2001 Robert M. Hanson, St. Olaf College, Northfield, MN //all rights reserved ntypes=Types.length TF=0 Choice=1 YesNo=2 image1=0 image2=0 function dowrite(doc,s,isrep) { if(arguments.length==2)isrep=true isrep?doc.open("text/html","replace"):doc.open() doc.write(""+s+"") doc.close() } function loadquestion(){ return doquestion(getrnd(3)) } function doquestion(itype){ if(itype==Choice)return doChoice() if(itype==TF)return doTF(0) if(itype==YesNo)return doTF(1) } function doChoice(){ var itype=gettwoimages() var isoptional=getrnd(2) var s1="" var s2="" var s="

How are these two compounds related?

" for(var i=0;i"+(s1.indexOf("They are")<0?"they are "+s1:s1)+"
" if(s1==s2 && itype==i)itype=i-1 s2=s1 } s+="they are identical
" s+="

" s+="" s+="" answer=itype sorry="They are "+stypeof(itype)+"." return s } function doTF(isyesno){ var itype=gettwoimages() var istrue=getrnd(2) var isthis=getrnd(2) var isoptional=getrnd(2) var swhatthis=stypeof(itype,isoptional) var i=itype while(i==itype)i=getrnd(ntypes) var swhatother=stypeof(i,isoptional) var swhat=(istrue?swhatthis:swhatother) answer=(istrue?0:1) if(isyesno){ var s="

Are these two compounds "+swhat+"?

Yes or No

" }else{ var s="

True or False:

" s+="These two compounds are "+swhat + ".

" } s+="" s+="

" sorry="They are "+swhatthis+"." return s } sorry="" function ans(i){ if(answer==i){alert("Correct.");getanother();return} alert("No. "+sorry) } function getanother(){parent.fraIndexE.setTimeout("doit(iagain)",100)} function stypeof(itype,isoptional){ var swhat="" if(itype<0){ swhat="identical" }else{ swhat=Types[itype] } var i=swhat.indexOf("|") if(i>=0){ if(isoptional){ swhat=swhat.substring(i+1,swhat.length) }else{ swhat=swhat.substring(0,i) } } return swhat } function getrnd(n){return Math.floor(Math.random()*n)} function gettwoimages(){ image1=getrnd(Data.length-1)+1 image2=image1 while(image2==image1 || DontCompare.indexOf("("+image1+","+image2+")")>=0 || DontCompare.indexOf("("+image2+","+image1+")")>=0)image2=getrnd(Data.length-1)+1 var itype=-1 for(i=0;i0 && Data[image1][i]!=Data[image2][i])itype=i } return itype }