Actually it seems that in your test, at least for firefox* the maximum height in CSS px is an issue.
*(In chrome the maximum scale()
multiplier/divider seems to be 10000)
If you add a third div with a fixed position, and you set your divs to this maximum CSSpx you can see that the higher the multiplier/divider is, the smaller the inner divs are :
s=150000;
document.getElementById('p').addEventListener('click', function(){
s*=1.1; doit();}, false);
document.getElementById('m').addEventListener('click', function(){
s/=1.1; doit();}, false);
function doit(){
document.getElementById('id2').style.transform = 'scale('+1/s+')';
document.getElementById('id1').style.transform = 'scale('+s+')';
document.getElementById('r').innerHTML = s;
}
#id1 { transform-origin: 0 0; transform: scale(1); width:17895697px; height: 17895697px; background:#AA00AA;}
#id2 {transform-origin: 0 0; transform: scale(1); width: 17895697px; height: 17895697px; background:#00AA00; }
#id3 { position: absolute; height: 100%; width: 100%;background:#AFAFAF;}
#p {position: fixed; top: 3em;}
#m {position: fixed; top: 3em; left: 3em;}
#r {position: fixed; top: 4em;}
<div id="id3"><div id="id2"><div id="id1">Bonjour</div></div></div>
<button id="p">+</button><button id="m">-</button><p id="r"></p>
Check this answer for more details : https://stackoverflow.com/a/24748165/3702797.
If we take the test case in the other way (container multiplies then contained divides), I can go to a multiplier of 10000
in chrome and 64424503296.0000038...
in FF :
Chrome
#id1 { transform: scale(10000); width: 33554428px; height: 33554428px; background: #AA00AA; }
#id2 { transform: scale(0.0001); width: 33554428px; height: 33554428px; background: #00AA00; }
Firefox
#id1 { transform: scale(10000); width: 17895697px; height: 17895697px; background:#AA00AA; }
#id2 { transform: scale(0.0001); width: 17895697px; height: 17895697px; background:#00AA00; }
Chrome Fiddle Firefox fiddle
Edit
This does mean that for firefox, the maximum scale()
multiplier is equal to the maximum browser CSS height/width
/ element height/width
. If your calculated element's height/width exceeds this limit, then your element won't be scaled anymore.
r.textContent = document.getElementById('id2').getBoundingClientRect().width +" instead of 1px*20.000.000";
#id2 {
transform: scale(2e+7);
width: 1px;
height: 1px;
background: #00AA00;
}
#id3 {
height: 100%;
width: 100%;
background: #AFAFAF;
}
#r {
position: fixed;
}
<div id="id3"> <div id="id2"></div> </div>
<p id="r"></p>
Chrome doesn't seem to be limited in such a way however…