/**********

          file:             help_kepler.js
          created:    20 apr 2007  
          topic:         support ftns for user choosing colors
          text:            Mastering JavaScript
          author:       James Jaworski
          pages:       <none>

          updates:
               25 june 2007  Revised for Kepler Problem use
               10 aug  2007  
                      1 )  Reformatted some of file
                      2 )  Changed  "help_poetry.js"  to  "help_kepler.js"

    
      **********/


      var  expiration_date = 
           "Tuesday, 10-Nov-20 23:12:40 GMT" ; // cookie valid until 10 nov 2020


      function    name_is_defined ( ck, nam )
         {
            var ss    = remove_blanks( ck ) ;
            var pairs = ss.split( ";" ) ;
            for( var j=0; j<pairs.length; j++ )
               {
                  var pair_split = pairs[j].split( "=" ) ;
                  if ( pair_split[0] == nam ) 
                     {
                        return true ;
                     }
               }
            return false ;

         } // name_is_defined


      function    remove_blanks ( ss )
         {
             var     temp = "" ;
             for ( var j=0;  j<ss.length;  j++ ) 
                 {
                     var     cc = ss.charAt( j ) ;
                      if ( cc != " " )
                         {
                               temp += cc ;
                         }
                 }
             return temp ;
        
         } // remove_blanks
       
      function     get_cookie_value ( kk, n )
         {
            var     ss = remove_blanks( kk ) ;
            var     pairs = ss.split( ";" ) ;
            for ( var j=0; j<pairs.length; j++ )
               {
                  var     pair_split = pairs[j].split( "=" ) ;
                  if ( pair_split[0] == n )
                     {
                          return pair_split[ 1 ] ;
                     }
               }
            return "" ;
       
         } // get_cookie_value

      function     read_cookie( ) 
         {
             //// alert( "Hello from top of read_cookie " ) ;

             var cookie = document.cookie ;

             kepler_text_color = "black" ;

             if ( name_is_defined( cookie, "kepler_background" )) 
                {
                    kepler_background = get_cookie_value ( cookie, "kepler_background" ) ;
                }
             else
                {
                    kepler_background = "white" ; 
                }
       
             if ( name_is_defined( cookie, "kepler_text_color" )) 
               {
                   kepler_text_color = 
                         get_cookie_value ( cookie, "kepler_text_color" ) ;
               }

             else  
               {
                   kepler_text_color = "black" ; 
               }

         } // read_cookie


      function     setCookie( ) 
         {
        
            var     new_cookie_1 = "kepler_background=" + kepler_background ;

            new_cookie_1 += "; expires="  +  expiration_date ; 
       
            window.document.cookie = new_cookie_1 ;
       
            var     new_cookie_2 = "kepler_text_color=" + kepler_text_color ;
       
            new_cookie_2 += "; expires="  +  expiration_date ; 
         
            window.document.cookie = new_cookie_2 ;
       
            window.location="kepler_problem_1.htm"

          } // setCookie


       function     set_prefs( ) 
          {
              //// alert( "Hello from top of set_prefs in help_kepler.js" ) ;
        
              bg_field     =  window.document.my_prefs_form.my_bg ;
              bg_index  =  bg_field.selectedIndex ;
       
              if ( bg_field.options[bg_index].text == "light gray" )     
                 {
                     kepler_background = "#eeeeee" ;  // smooth light gray
                 }
              else if ( bg_field.options[bg_index].text == "blanched almond" )
                 {
                    kepler_background = "blanchedalmond" ; 
                 }
              else
                 {
                    kepler_background  = bg_field.options[bg_index].text ;
                 }
            
              fg_field         =  window.document.my_prefs_form.my_fg ;
              fg_index      =  fg_field.selectedIndex ;
              kepler_text_color  =  fg_field.options[fg_index].text ;
              setCookie( ) ;
       
           } // set_prefs

        function create_prefs_form( ) 
           {
              document.writeln( '<form   name="my_prefs_form">' ) ;

              //// document.writeln( 'Background color: ' ) ;

              document.writeln( "<span  class='gmt_choose_color' >"  +
                                "&nbsp;&nbsp;&nbsp;&nbsp;   Background color: </span>" ) ;

              document.writeln( '<select  name="my_bg" size="1" >' ) ;
              document.writeln( '<option>aqua' ) ;
              document.writeln( '<option>blanched almond' ) ;
              document.writeln( '<option>blue' ) ;
              document.writeln( '<option>black' ) ;
                      //// document.writeln( '<option>rough_gray' ) ;        
              document.writeln( '<option>light gray' ) ;              
              document.writeln( '<option>lime' ) ;
              document.writeln( '<option>orange' ) ;
              document.writeln( '<option>red' ) ;
              document.writeln( '<option>tan' ) ;
              document.writeln( '<option SELECTED >white' ) ;  
              document.writeln( '<option>yellow' ) ;        
              document.writeln( '</select >' ) ;

              //// document.writeln( ' Text color: ' ) ;

              document.writeln( "<span  class='gmt_choose_color' >"  +
                                "&nbsp Text color: </span>" ) ;

              document.writeln( '<select  name="my_fg" size="1" >' ) ;
              document.writeln( '<option>aqua' ) ;        
                
              document.writeln( '<option SELECTED >black' ) ;
              document.writeln( '<option>blue' ) ;  
              document.writeln( '<option>gray' ) ;  
              document.writeln( '<option>green' ) ; 
              document.writeln( '<option>lime' ) ;        
              document.writeln( '<option>orange' ) ;
              document.writeln( '<option>red' ) ;
              document.writeln( '<option>silver' ) ;                    
              document.writeln( '<option>tan' ) ;
              document.writeln( '<option>white' ) ;
              document.writeln( '<option>yellow' ) ;        
              document.writeln( '</select >' ) ;

              document.write( ' &nbsp; &nbsp; ' ) ;  // two spaces     

              document.writeln( "<input   "                    +
                                "class='gmt_set_color_btn'"   +
                                "type='button'"                            +
                                "value='Set Colors'"                   +
                                "onClick='set_prefs( )'" ) ;
              document.writeln( '</form>' ) ;

           } // create_prefs_form