JSFiddle - React, Tailwind, and code Playground
by Daedalus
HTML
<textarea class="blah">4</textarea>
<textarea class="blah">44</textarea>
<textarea class="blah"> 4</textarea>
<textarea class="blah"> 44</textarea>
<textarea class="blah">
44
</textarea>
<textarea class="blah">\0034</textarea>
JavaScript
var entries = document.getElementsByClassName('blah');
for (var i = 0; i<entries.length; i++) {
var val = entries[i].value;
console.log(val.match(/^\d+$/),val.toString());
}