function addEvent(elm, evType, fn, useCapture){  //cross-browser event handling for IE5+, NS6+, and Mozilla/Gecko By Scott Andrew                           
        if(elm.addEventListener){                                                                                                                           
	                elm.addEventListener(evType, fn, useCapture);                                                                                               
			                return true;                                                                                                                                
					        }else if(elm.attachEvent){                                                                                                                          
						                var r = elm.attachEvent('on' + evType, fn);                                                                                                 
								                return r;                                                                                                                                   
										        }else{                                                                                                                                              
											                elm['on' + evType] = fn;                                                                                                                    
													        }                                                                                                                                                   
														}   
//Get cookie routine by Shelley Powers 

function get_cookie(Name) {

  var search = Name + "="
  
    var returnvalue = "";
    
      if (document.cookie.length > 0) {
      
          offset = document.cookie.indexOf(search)
	  
	      // if cookie exists
	      
          if (offset != -1) { 
		  
        offset += search.length
			
      // set index of beginning of value
			      
    end = document.cookie.indexOf(";", offset);
				    
  // set index of end of cookie value
	  
if (end == -1) end = document.cookie.length;				
  returnvalue=unescape(document.cookie.substring(offset, end))
    }
}
 return returnvalue;
 }

function IsNumeric(strString)
   //  check for valid numeric strings	
      {
         var strValidChars = "0123456789.-";
	    var strChar;
	       var blnResult = true;
	       
	          if (strString.length == 0) return false;
		  
		     //  test strString consists of valid characters listed above
		        for (i = 0; i < strString.length && blnResult == true; i++)
			      {
			            strChar = strString.charAt(i);
				          if (strValidChars.indexOf(strChar) == -1)
					           {
						            blnResult = false;
							             }
								           }
									      return blnResult;
									         }

//Specify affected tags. Add or remove from list:
var tgs = new Array( 'div','td','tr','p');

//Specify spectrum of different font sizes:
//var szs = new Array( 'xx-small','x-small','small','medium','large','x-large','xx-large' );
szs=new Array('9px','10px','11px','12px','13px','14px','15px','17px');
var startSz=2;

function ts ( trgt,inc) {
	
	if (!document.getElementById) return
	var d = document,cEl = null,sz = startSz,i,j,cTags;
	
	//alert(startSz);
	
	sz += inc;
	
	if ( sz < 0 ) sz = 0;
	if ( sz > 7 ) sz = 7;
	startSz = sz;
	document.cookie="puvodnivelikost="+startSz+";path=/";
	
	if ( !( cEl = d.getElementById( trgt ) ) ) cEl = d.getElementsByTagName( trgt )[ 0 ];

	cEl.style.fontSize = szs[ sz ];

	for ( i = 0 ; i < tgs.length ; i++ ) {
		cTags = cEl.getElementsByTagName( tgs[ i ] );
		for ( j = 0 ; j < cTags.length ; j++ ) cTags[ j ].style.fontSize = szs[ sz ];
	}
	
	
}

//function nacti(){ var velikost=get_cookie("velikost"); if(velikost != ''){ ts('body',startSz+velikost);} alert(velikost);}
function nacti(){
var prevod1 = new Array(-2,-1,0,1,2,3,4,5);
var velikost1=get_cookie('puvodnivelikost');
//alert(velikost1);
if(IsNumeric(velikost1)){
ts('body',prevod1[velikost1]);
}else {ts('body',0);}
}

function velikostn(){
var prevod = new Array(2,1,0,-1,-2,-3,-4,-5);
var velikost=startSz;
//alert(startSz);
ts('body',prevod[velikost]); 
}

addEvent(window, 'load', nacti, false);