Calculate font-size required for text to fill desired space
HTML
<div id="element"></div>
CSS
#element {
font-family: sans-serif;
//white-space: nowrap;
height: 130px;
width: 500px;
}
JavaScript
var x = 1;
var y = 200; //staring font-size
txt = "this text should fill the div precisely";
$('#element').html(txt)
.css('font-size', y + 'px');
var element = document.querySelector('#element');
while (x) {
if ((element.offsetHeight < element.scrollHeight) || (element.offsetWidth < element.scrollWidth)) {
element.style.backgroundColor = "yellow";
element.style.fontSize = y + 'px';
y--;
} else {
x = 0;
element.style.backgroundColor = "blue";
}
}