JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="body_content_foo"></textarea>
<textarea id="i_am_different"></textarea>
<textarea id="body_content_bar"></textarea>

JavaScript

function getElementsByIdStartsWith(selectorTag, prefix) {
    var items = [];
    var elements = document.getElementsByTagName(selectorTag);
    for (var i = 0; i < elements.length; i++) {
        if (elements[i].id.lastIndexOf(prefix, 0) === 0) {
            items.push(elements[i]);
        }
    }

    return items;
}

var affectedElements = getElementsByIdStartsWith("textarea", "body_content");
for(var i = 0; i < affectedElements.length; i++) {
    affectedElements[i].innerHTML = 'I was found';
}