There are couple way to do it.
1. Through JavaScript. Note that querySelectorAll return list of elements, therefore a loop is required to iterate all the elements in it.
function myFunction() {
document.querySelectorAll('h1, h2').forEach(function(tag) {
tag.innerHTML = tag.innerHTML.toUpperCase();
});
}
myFunction() ;
2. CSS
h1, h2 {
text-transform: uppercase;
}
CP_upper case - JSFiddle[
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