function increaseFontSize() {
   var p = document.getElementsByTagName('body');
    if(p[0].style.fontSize) {
		var s = parseInt(p[0].style.fontSize.replace("px",""));
    } else {
        var s = 12;
    }
	s += 1;
	p[0].style.fontSize = s+"px"
}

function decreaseFontSize() {
	var p = document.getElementsByTagName('body');
	if(p[0].style.fontSize) {
		var s = parseInt(p[0].style.fontSize.replace("px",""));
	} else {
		var s = 12;
	}
	s -= 1;
	p[0].style.fontSize = s+"px"
}

function standartFontSize() {
	var p = document.getElementsByTagName('body');
	p[0].style.fontSize = "12px"
}