JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" class="some"></input>
<input type="text" ></input>
<input type="text" class="some"></input>
<input type="text" ></input>

JavaScript

if(document.getElementsByClassName === undefined) {
    document.getElementsByClassName = function(classList) {           
        var i,j,
        list = document.getElementsByTagName('*'),
        length = list.length, 
        classArray = classList.split(/\s+/),
        classes = classArray.length,
        result = [], i,j
        for(i = 0; i < length; i++)
            for(j = 0; j < classes; j++)
                if(list[i].className.search('\\b' + classArray[j] + '\\b') != -1) {
                    result.push(list[i])
                    break;
                }
        return result
    }
}
var some = document.getElementsByClassName('some');
for(var i=0; i < some.length; ++i)
    some[i].readOnly=true;