/* checked with jsLint on 2009 01 02 */
// styles should be set for idObj,HdrClass, and
// all class, classbirth, classdeath classes used 
var EndYear=1999; var StartYear=1900;   // defaults for header centuries
var HeaderYear;
var timeCopy="";var scale=2; // increase scale to reduce horizontal scroll
//function to draw header or footer line
function writeHeaders(StartYr,EndYr,HdrClass) {// century headings
  StartYear=Math.floor(StartYr/100)*100; // start at century x
  EndYear=Math.floor(EndYr/100)*100;     // end at century y
  timeCopy+='<tr>';
  for(HeaderYear=StartYear;HeaderYear<=EndYear;HeaderYear=HeaderYear+100){
    timeCopy+='<th class="'+HdrClass+'" colspan="'+100/scale;
    timeCopy+='">'+HeaderYear+'&#39;s<\/th>';
    }
  timeCopy+='<\/tr>';
}
//function to draw individual timeline
function lifeLine(BirthYear,DeathYear,Class,Text) {
  var LeftColspan=0; var RightColspan=0; var MidColspan=0;
  if(BirthYear>StartYear){LeftColspan=BirthYear-StartYear;}
  if(BirthYear<StartYear){MidColspan=DeathYear-StartYear+1;}
    else {MidColspan=DeathYear-BirthYear+1;}
  if(DeathYear!=='-') {RightColspan=EndYear+100-DeathYear;}
  timeCopy+='<tr class="main">';
  if(LeftColspan>0){
    timeCopy+='<td colspan="'+LeftColspan/scale+'">&nbsp;<\/td>';}
  timeCopy+='<td colspan="'+MidColspan/scale+'" class="'+Class+'">';
  timeCopy+='<table class="main"><tr>';
  timeCopy+='<td class="'+Class+'birth">'+BirthYear+'<\/td>';
  timeCopy+='<td width="100%" class="'+Class+'">'+Text+'<\/td>';
  timeCopy+='<td class="'+Class+'death">'+DeathYear+'<\/td>';
  timeCopy+='<\/tr><\/table><\/td>';
  if(RightColspan>0){
    timeCopy+='<td colspan="'+RightColspan/scale+'">&nbsp;<\/td>';}
  timeCopy+="<\/tr>";
}
// main table building function
function TimeLines(idObj) {
  timeCopy+='<table class="main">';writeHeaders(1740,1999,'head');
//lifeLine(start,end,'class','name');
  lifeLine(1743,1826,'male','<a href="#jef">Jefferson<\/a>');
  lifeLine(1802,1875,'male','<a href="#whe">Wheatstone<\/a>');
  lifeLine(1805,1881,'male','<a href="#kas">Kasiski<\/a>');
  lifeLine(1835,1903,'male','<a href="#ker">Kerckhoffs<\/a>');
  lifeLine(1889,1958,'male','<a href="#yar">Yardley<\/a>');
  lifeLine(1891,1969,'male','<a href="#fri">Friedman<\/a>');
  lifeLine(1912,1954,'male','<a href="#tur">Turing<\/a>');
  lifeLine(1905,1998,'male','<a href="#flo">Flowers<\/a>');
//writeHeaders(1740,1999,'head'); // and a footer 
  timeCopy+='<\/table>';
  document.getElementById(idObj).innerHTML=timeCopy;
}