Assuming modernizr is loaded, are there any performance issues when referencing elements by class name using the code snips below?
One is using the elementName.className .className the other is simply using .className .className
HTML:
<html class="touch ...">
<head>...</head>
<body>
<div class="icon"></div>
<div class="icon"></div>
<div class="icon"></div>
</body>
</html>
CSS:
.icon { display: none; }
html.touch .icon { display: inline-block;}
vs
.icon { display: none; }
.touch .icon { display: inline-block;}
no, none at all.
There may be once you get to hundreds of thousands of rules/selectors, but there will almost always without a shadow of a doubt be dozens of other perf issues that need to be addressed before your css selectors.