function isInteger(s){
 for(i=0;i<s.length;i++){   
  var c=s.charAt(i);
  if((c<"0") || (c>"9")) return false;
 }
 return true;
}

function _getInt(str,i,minlength,maxlength){
 for(var x=maxlength;x>=minlength;x--){
  var token=str.substring(i,i+x);
  if(token.length<minlength){return null;}
  if(isInteger(token)){return token;}
 }
 return null;
}
	
function isDate(val){
 if (val != ""){
  val=val+""; var format="M/d/y"; var i_val=0; var i_format=0; var c=""; var token="";
  while(i_format<format.length){
   c=format.charAt(i_format);
   token="";
   while((format.charAt(i_format)==c) && (i_format<format.length)){token += format.charAt(i_format++);}
   if(token=="y"){
    year=_getInt(val,i_val,2,4);
    if(year==null){return false;}
    i_val += year.length;
    if(year.length==2){if (year>70){year=1900+(year-0);}else{year=2000+(year-0);}}
   }else if(token=="M"){
    month=_getInt(val,i_val,token.length,2);
    if(month==null||(month<1)||(month>12)){return false;}
    i_val+=month.length;
   }else if(token=="d"){
    date=_getInt(val,i_val,token.length,2);
    if(date==null||(date<1)||(date>31)){return false;}
    i_val+=date.length;
   }else{
    if(val.substring(i_val,i_val+token.length)!=token){return false;}else{i_val+=token.length;}
   }
  }
  if(i_val != val.length){return false;}
  if(month==2){
   if(((year%4==0)&&(year%100 != 0))||(year%400==0)){if(date>29){return false;}}
   else{if(date>28){return false;}}
   }
  if((month==4)||(month==6)||(month==9)||(month==11)){if(date>30){return false;}}
 }
 return true;
}

function zval(){
 var dtemp=document.getElementById("zarm").value + "/" + document.getElementById("zard").value + "/" + document.getElementById("zary").value
 if(!isDate(dtemp)){
  alert("Please select a valid date.");
  document.getElementById("zarm").focus();
  return (false);
 }else{
  var adate=new Date(document.getElementById("zary").value, (document.getElementById("zarm").value-1), document.getElementById("zard").value);
  var atime=adate.getTime()
  var thisdate=new Date();
  thisdate=new Date(thisdate.getUTCFullYear(),thisdate.getMonth(),thisdate.getDate());
  if(Math.round((atime-thisdate.getTime())/86400000)<2){
   alert("For standard booking, you must choose an arrival date at least two days from today.\nFor immediate arrivals please call us at 800-641-5660.");
   document.getElementById("zarm").focus();
   return (false);
  }
 }
}