JSFiddle - React, Tailwind, and code Playground

HTML

don't work <br>
<form id="mainForm">
    <select name="selectTypeParty" onchange="selectTypeParty(this.value)">
        <option value="melee">Melee</option>
        <option value="classic">Classic</option>
    </select>
</form><br>
work <br>
<form id="mainForm2">
    <select name="selectTypeParty" onchange="test(this.value)">
        <option value="melee">Melee</option>
        <option value="classic">Classic</option>
    </select>
</form><br>
work <br>
<form id="mainForm3">
    <select name="test" onchange="selectTypeParty(this.value)">
        <option value="melee">Melee</option>
        <option value="classic">Classic</option>
    </select>
</form>

JavaScript

function selectTypeParty(value) {
	alert(value);
}
function test(value) {
	alert(value);
}