The HTML variable TYPEDRILL contains the names of the files that are the targets for the values of the variable TYPE. 
     if type='Corn' then
        typedrill='HREF="type1_body.html"';
     else if type='Rice' then
        typedrill='HREF="type2_body.html"';
     else if type='Wheat' then
        typedrill='HREF="type3_body.html"';
 run;