prueba fontsize
otra prueba
by femfoyou
HTML
font size: <input id="font-input" type="range" min="0" max="250" value="65"/>
JavaScript
var fontInput = document.getElementById("font-input");
var charSize = 65;
var cellSize = charSize/7;
fontInput.oninput = function(){
charSize = parseInt(fontInput.value);
cellSize = charSize/7;
}