ok = false; pick = 1;
if (navigator.userAgent.indexOf ("Mozilla") != -1) {
  ok = parseInt(navigator.appVersion.substring(0,1)) >= 3
} else {}

   if (ok == 1) {
      boutonx = new Image(127,25)
      boutonx.src = "image/bouton_x.gif"
      boutono = new Image(127,25)
      boutono.src = "image/bouton_o.gif"
   }
   function un(nom) {
       if (ok == 1) {
          if ((nom == "f1")&&(pick!=1)) {document.f1.src = boutono.src;}
          if ((nom == "f2")&&(pick!=2)) {document.f2.src = boutono.src;}
          if ((nom == "f3")&&(pick!=3)) {document.f3.src = boutono.src;}
          if ((nom == "f4")&&(pick!=4)) {document.f4.src = boutono.src;}
          if ((nom == "f5")&&(pick!=5)) {document.f5.src = boutono.src;}

          return true;
       }
   }
   function deux(nom) {
       if (ok == 1) {
          if ((nom == "f1")&&(pick!=1)) {document.f1.src = boutonx.src;}
          if ((nom == "f2")&&(pick!=2)) {document.f2.src = boutonx.src;}
          if ((nom == "f3")&&(pick!=3)) {document.f3.src = boutonx.src;}
          if ((nom == "f4")&&(pick!=4)) {document.f4.src = boutonx.src;}
          if ((nom == "f5")&&(pick!=5)) {document.f5.src = boutonx.src;}
   
          return true;
       }
   }
   function trois(nom) {
       if (ok == 1) {
          if (pick==1) {document.f1.src = boutonx.src;}
          if (pick==2) {document.f2.src = boutonx.src;}
          if (pick==3) {document.f3.src = boutonx.src;}
          if (pick==4) {document.f4.src = boutonx.src;}
          if (pick==5) {document.f5.src = boutonx.src;}
       
          if ((nom == "f1")&&(pick!=1)) {document.f1.src = boutono.src; pick=1}
          if ((nom == "f2")&&(pick!=2)) {document.f2.src = boutono.src; pick=2}
          if ((nom == "f3")&&(pick!=3)) {document.f3.src = boutono.src; pick=3}
          if ((nom == "f4")&&(pick!=4)) {document.f4.src = boutono.src; pick=4}
          if ((nom == "f5")&&(pick!=5)) {document.f5.src = boutono.src; pick=5}

		  if (pick==1) {document.f1.src = boutono.src;} 
		  if (pick==2) {document.f2.src = boutono.src;} 
		  if (pick==3) {document.f3.src = boutono.src;} 
		  if (pick==4) {document.f4.src = boutono.src;} 
		  if (pick==5) {document.f5.src = boutono.src;} 
		 		  
          return true;
       }
   }