if(document.images)
 {
 main=new Image(140,40)
 main.src="main1.gif"
 safety=new Image(140,40)
 safety.src="safety1.gif"
 theory=new Image(140,40)
 theory.src="theory1.gif"
 design=new Image(140,40)
 design.src="design1.gif"
 construct=new Image(140,40)
 construct.src="construct1.gif"
 m1_=new Image(140,40)
 m1_.src="m1_1.gif"
 m1b_=new Image(140,40)
 m1b_.src="m1b_1.gif"
 m2_=new Image(140,40)
 m2_.src="m2_1.gif"
 links=new Image(140,40)
 links.src="links1.gif"
 emailme=new Image(140,40)
 emailme.src="emailme1.gif"
 next=new Image(140,40)
 next.src="next1.gif"
 prev=new Image(140,40)
 prev.src="prev1.gif"
 back=new Image(140,40)
 back.src="back1.gif"
 }
function swap(nam,hi)
 {
 if(document.images)
  {
  var i = 0;
  while (i < document.images.length)
   {
   if (nam == document.images[i].name) break;
   i++;
   }
  document.images[i].src=document.images[i].name+hi+".gif";
  }
 }
function modif()
 {
 document.write("last modified on ");
 document.write(document.lastModified);
 }

function danger()
 {
 if(self.moveBy)
  {
  for(a=5;a>0;a--)
   {
   self.moveBy(0,a);
   self.moveBy(a,0);
   self.moveBy(0,-a);
   self.moveBy(-a,0);
   }
  }
 }