JSFiddle - React, Tailwind, and code Playground

HTML

<form id="testform">
    <input type="checkbox" name="test_checkbox[0]" id="test" checked="checked" value="true"/>
    <input type="checkbox" name="test_checkbox[1]" id="test1" checked="checked" value="true"/>
<span>click</span>
</form>

JavaScript

$('span').click(function() {
     var str=$('form input:not([type="checkbox"])').serialize();
    var str1=$("form input[type='checkbox']").map(function(){return this.name+"="+this.checked;}).get().join("&");
    if(str1!="" && str!="") str+="&"+str1;
    else str+=str1; 
    alert(str);
})