var form=document.getElementById('saisie');form.a.focus();
var e0=document.getElementById('e0');var e1=document.getElementById('e1');var e2=document.getElementById('e2');
var d0=document.getElementById('d0');var d1=document.getElementById('d1');var d2=document.getElementById('d2');
function valid(a,b)
{var test=false;
 s=a.length;if(!s){test=true;}else{for(i=0;i<s;i++){t=a.substring(i,i+1);if((t<"0")||(t>"9")){test=true;}}}
 s=b.length;if(!s){test=true;}else{for(i=0;i<s;i++){t=b.substring(i,i+1);if((t<"0")||(t>"9")){test=true;}}}
 return(test);
}
function pgcd_e()
{var a=form.a.value;var b=form.b.value;
 e1.innerHTML='';e2.innerHTML='';
 if(valid(a,b))
 {e0.innerHTML='<span class="cr">Il faut saisir des nombres entiers !</span>';}
 else if((a==0)||(b==0))
 {e0.innerHTML='<span class="cr">Les nombres doivent être strictement positifs !</span>';}
 else
 {e0.innerHTML='<span class="cv s">Algorithme d\'Euclide :</span>';
  if(a-b>0){var A=a;var B=b;}else{var A=b;var B=a;}i=0;
  while(B)
  {R=A%B;Q=Math.floor(A/B);
   if(i){e1.innerHTML+='= ';}else{e1.innerHTML+='&nbsp;&nbsp;&nbsp;';}
   e1.innerHTML+='PGCD('+A+','+B+')<br />';
   e2.innerHTML+=A+'='+B+'&times;'+Q+'+'+R+'<br />';
   A=B;B=R;i++;}
  if(i==1){s='';}else{s='s';}
  e1.innerHTML+='= <span class="cv">'+A+'</span>';
  e2.innerHTML+='<span class="cv">( '+i+' itération'+s+' )</span>';
 }
}
function pgcd_d()
{var a=form.a.value;var b=form.b.value;
 d1.innerHTML='';d2.innerHTML='';
 if(valid(a,b))
 {d0.innerHTML='<span class="cr">Il faut saisir des nombres entiers !</span>';}
 else if((a==0)||(b==0))
 {d0.innerHTML='<span class="cr">Les nombres doivent être strictement positifs !</span>';}
 else
 {d0.innerHTML='<span class="cv s">Algorithme des différences :</span>';
  if(a-b>0){var A=a;var B=b;}else{var A=b;var B=a;}i=0;
  while((B)&&(i<500))
  {D=A-B;
   if(i){d1.innerHTML+='= ';}else{d1.innerHTML+='&nbsp;&nbsp;&nbsp;';}
   d1.innerHTML+='PGCD('+A+','+B+')<br />';
   d2.innerHTML+=A+'&minus;'+B+'='+D+'<br />';
   A=Math.max(B,D);B=Math.min(B,D);i++;}
  if(i==1){s='';}else{s='s';}
  if(i<500){d1.innerHTML+='= <span class="cv">'+A+'</span>';}else{d1.innerHTML+='= <span class="cr">Abandon...</span>';}
  d2.innerHTML+='<span class="cv">( '+i+' itération'+s+' )</span>';
 }
}