JSFiddle - React, Tailwind, and code Playground

HTML

<input type='checkbox' name='chkRelatedTopics' value='${subject}'/>
<input type='checkbox' name='chkRelatedTopics' value='${subject2}'/>
<input type='checkbox' name='chkRelatedTopics' value='${subject3}'/>
<input type='checkbox' name='chkRelatedTopics' value='${subject4}'/>

JavaScript

var txtTopicsGuids = "";

var checkedTopics = document.getElementsByName("chkRelatedTopics");
console.log(checkedTopics.length);
console.log($(checkedTopics));
$(checkedTopics).each(function() {
    if ($(this).is(":checked")) {
        console.log(this.name);
    }

});