function getdoc(a)
{
	var PLUS ="+"
	var STRPRX =''
	var STRSUX =''
	var StartPos, PlusChar, PlusCharNum, StrChar, PlusStartDb, DNum, DocNum, PlusStart
	var LocationStr, StrPlus, StrMinus, StrDb, Str1, Str2, Str, StrView
		 LocationStr=document.location + ""
		 PlusStart = LocationStr.indexOf("+")
		 PlusStart += 1
		 Str1 = LocationStr.substring(0, PlusStart)
		PlusChar = PlusStart
		PlusCharNum=0
		 for   ( PlusChar; StrChar = LocationStr.substring(PlusChar, PlusChar+1); PlusChar++)
		 {
			 if   (StrChar == PLUS)
			 { 
                                                           if (PlusCharNum == 0)
				  {    
                                                                      StrView = LocationStr.substring(PlusStart, PlusChar)
                                                                      
                                                                       PlusCharNum++
                                                                      StartPos = PlusChar + 1
                                                                      continue
				  } 
                                                            if (PlusCharNum == 1)
				  {
                                                                        StrDb = LocationStr.substring(StartPos, PlusChar)
					                                                                         PlusCharNum++
					 StartPos = PlusChar + 1
					continue
                                                            } 
                                                            break
			  }
		  }
		 Str2 = LocationStr.substring(PlusChar, 90)
		 DocNum = LocationStr.substring(StartPos, PlusChar)
		 DNum = eval(DocNum)
		 if ( a < 0 )
		 {
			  DNum -= 1
			  if (DNum <= 0)
			  { alert("There are no more documents before this one in this subdatabase!")
			      DNum =  1
			  }
		 }
		 else
		 {
			  DNum += 1
		 }
		Str =  STRPRX + Str1 + StrView +  '+' + StrDb +  '+' +DNum + Str2 + STRSUX
		
                            window.location = Str
		window.location.open
 }