function changeFont(operation, size)
{
	var elem,divs;
	if (!operation) {size=-size;};//check cur operation + or -
	elem = document.getElementById("content");
	if (elem) {
			changeelementFontSize(elem,size,3,25,9);//change font size for content element
			divs= elem.getElementsByTagName("div");
			for(i=0;i<divs.length;i++)
			{
				if(divs[i].className == "articletitle") {
					changeelementFontSize(divs[i],size,14,36,20);
				} else {
					//changeelementFontSize(divs[i],size,9,25,9);
				}
			}
	}
}

function changeelementFontSize(elem,size,min,max,avrg){
var el_fs_len,cursize;
if (elem){
    el_fs_len=String(elem.style.fontSize);
    if ((el_fs_len.length>0) && (isNaN(el_fs_len) )){//exists and not number -delete last 2 chars
    		el_fs_len=el_fs_len.slice(0,-2);//delete last 2 chars with information about size of element
	}	
	//check min max length of element font size	
    if(el_fs_len.length==0) {cursize=avrg;//set avrg val
    } else {//determinate size is it max or not
		cursize=Number(el_fs_len);
		if (cursize<min) {cursize=min};
		if (cursize>max) {cursize=max};
	}
	//change to new one
	cursize=cursize+size;
	//alert(cursize);
	elem.style.fontSize =String(cursize)+ "pt";	
 }//elem	
}