// book.js all code and interface copyright Mike Capstick 2004
// updated to allow mystyle.css 
// updated to hide tab at start and end of book 06/08/04
// requires generated.js 

 //initialise all  stylesheets to 1 - disabled
 var a=1;b=1;c=1;d=1;defaultstyle=1;

function startup(){

   pagenumber=0; // initialise pagenumber

   //no page numbers on title page
   document.getElementById('foot1').firstChild.nodeValue=''   
   document.getElementById('foot2').firstChild.nodeValue=''

   // remove chapter details from title and contents
   document.getElementById('chapterleft').firstChild.nodeValue=''
   document.getElementById('chapterright').firstChild.nodeValue='' 

  // hide backtab and show nexttab button on opening page load
  document.getElementById('backtab').style.visibility='hidden'
  document.getElementById('nexttab').style.visibility='visible'
}

function switcher(i){

// get style sheet value from the parent  dropbox, parent.stylesheet
//    parent.stylesheet =i.options[i.selectedIndex].value;
    parent.stylesheet =i;
    pagestyler(); // now call stylesheet changer
}

function pagestyler(){
  //turn on required stylesheet - disabled=0

//alert(parent.stylesheet)

 //re-initialise all  stylesheets to 1 - disabled
    a=1;b=1;c=1;d=1;defaultstyle=1;
    if (parent.stylesheet=='1'){a=0}
    if (parent.stylesheet=='2'){b=0}
    if (parent.stylesheet=='3'){c=0}
    if (parent.stylesheet=='4'){d=0}

    if (parent.stylesheet=='0'){defaultstyle=0}   //default style

    document.getElementsByTagName("link")[0].disabled=a;
    document.getElementsByTagName("link")[1].disabled=b;
    document.getElementsByTagName("link")[2].disabled=c;
    document.getElementsByTagName("link")[3].disabled=d;

    document.getElementsByTagName("link")[4].disabled=defaultstyle; 

// turned off due a bug in IE6 iframe restyle
// style iframe containing right and left pages with selected stylesheet using the .page style
// alert(frames['rightpage'].document.getElementsByTagName('link')[0].disabled)
//        parent.frames['rightpage'].document.getElementsByTagName("link")[0].disabled=a;
//        parent.frames['rightpage'].document.getElementsByTagName("link")[1].disabled=b;
//        parent.frames['rightpage'].document.getElementsByTagName("link")[2].disabled=c;
//        parent.frames['rightpage'].document.getElementsByTagName("link")[3].disabled=defaultstyle; 
//        parent.frames['leftpage'].document.getElementsByTagName("link")[0].disabled=a;
//        parent.frames['leftpage'].document.getElementsByTagName("link")[1].disabled=b;
//        parent.frames['leftpage'].document.getElementsByTagName("link")[2].disabled=c;
//        parent.frames['leftpage'].document.getElementsByTagName("link")[3].disabled=defaultstyle; 

}

function contents(){
   pagenumber=0;  //reset to start of book

   document.getElementById('backtab').style.visibility='hidden'
   document.getElementById('nexttab').style.visibility='visible'

   // remove chapter details from title and contents
   document.getElementById('chapterleft').firstChild.nodeValue=booktitle
   document.getElementById('chapterright').firstChild.nodeValue=''

   //no page numbers on title page
   document.getElementById('foot1').firstChild.nodeValue=''   
   document.getElementById('foot2').firstChild.nodeValue=''

   //set start pages to title.html and contents.html
   document.getElementById('leftpage').src=pages[0]   
   document.getElementById('rightpage').src=pages[1]  
}

function next(x){

if (pagenumber<maxpage)
     {// turn pages
         pagenumber=pagenumber+2*x;
         document.getElementById('leftpage').src=pages[pagenumber]
         document.getElementById('rightpage').src=pages[pagenumber+1]

         if (pagenumber>=maxpage)
            {document.getElementById('nexttab').style.visibility='hidden'}

         document.getElementById('backtab').style.visibility='visible'

         // add chapter number
         document.getElementById('chapterleft').firstChild.nodeValue=booktitle
         document.getElementById('chapterright').firstChild.nodeValue=''

        //adjust page numbers
         leftpagenumber=pagenumber
         document.getElementById('foot1').firstChild.nodeValue='page '+leftpagenumber
         rightpagenumber=pagenumber+1
         document.getElementById('foot2').firstChild.nodeValue='page '+rightpagenumber 
         // switcher(i);
     }
}

function back(){
// ensure we can see the nexttab button
        document.getElementById('nexttab').style.visibility='visible'
         pagenumber=pagenumber-2;
         // check if we are the title page and remove page/chapter details if we are
         if (pagenumber==0)
                 {contents(); // do function contents()
                   document.getElementById('backtab').style.visibility='hidden'} 
         else {
                document.getElementById('leftpage').src=pages[pagenumber];
                document.getElementById('rightpage').src=pages[pagenumber+1];

                // add chapter number
                document.getElementById('chapterleft').firstChild.nodeValue=booktitle
                document.getElementById('chapterright').firstChild.nodeValue=''

                //adjust page numbers
                leftpagenumber=pagenumber;
                document.getElementById('foot1').firstChild.nodeValue='page '+leftpagenumber
                rightpagenumber=pagenumber+1
                document.getElementById('foot2').firstChild.nodeValue='page '+rightpagenumber 
               } //end of are we on title page
        
}

function about(){
     newwin1=window.open('about.html', 'UBooks', 'width=600,height=450,left=50,top=100,screenX=50,screenY=100'); 
}

function help(){
     newwin2=window.open('help.html', 'UBooks', 'width=600,height=450,left=50,top=100,screenX=50,screenY=100'); 
}