var fnt = 100;
function bigger() {
fnt = fnt + 10;
document.getElementById('l_content').style.fontSize = fnt + '%';
document.getElementById('big').title =  fnt + '%';
document.getElementById('sma').title =  fnt + '%';
}

function smaler() {
fnt = fnt - 10;
document.getElementById('l_content').style.fontSize = fnt + '%';
document.getElementById('big').title =  fnt + '%';
document.getElementById('sma').title =  fnt + '%';
}

function reset_font() {
fnt = 100;
document.getElementById('l_content').style.fontSize = '100%';
document.getElementById('big').title =  'grösser';
document.getElementById('sma').title = 'kleiner';
}