function IsInt(objStr)
{
     var  reg=/^\+?[0-9]*[1-9][0-9]*$/;
    var r=objStr.match(reg);
    if(r==null)
    {
	
        return false;
    }
    else
    {     
	   
        return true;
    }
	

}
function check()
{
    
  var q1=document.getElementById('vwq').value;
  var q2=document.getElementById('hqty').value;
  var model=document.getElementById('model').value;
  var sprice=document.getElementById('sprice').value;

 if(IsInt(q1))
  { 	 
	if(IsInt((parseInt(q1)/parseInt(q2)).toString()))
	 {
	  return true;
	 }
	 else
	 {
	 alert('The quantity must be a multiple of '+q2+' model '+model);
	 return false;
	 }
  }
 else
 {
  alert('The quantity must be a multiple of '+q2+' model '+model);
  return false;
 }
}
function checks()
{
  var q1=document.getElementById('vwq').value;
  var q2=document.getElementById('hqty').value;
  var model=document.getElementById('model').value;
  if(IsInt(q1))
  {
	if(parseInt(q1)>=parseInt(q2))
	{
	  return true;
	}
	else
	{
		alert('There is a minimum order of at least '+q2+' units for model '+model);
		return false;
	}
  }else
  {
	alert('The quantity must be a multiple of 1 model '+model);
	return false;
  }
}
////////////////////////////////////////turn over
function showpage(pn,tn)
{
  var n=parseInt(tn);
  var sn=parseInt(pn)
  var prev=document.getElementById("prev");
  var next=document.getElementById("next");

if (sn!=0)
 { 
  for (var i=1;i<n+1;i++)
   {
   var page=document.getElementById('page'+i);
    if(sn==i)
    {  
         if(sn==n)
        {
         prev.value=sn-1;
         next.value=0;
        }
        else if(sn==1)
       {
         prev.value=0;
         next.value=sn+1;
        }
       else
         {
	  prev.value=sn-1;
	  next.value=sn+1;
        }
     page.style.display="block";
     }
    else
	{
     page.style.display="none";
    }
  }
  }
}