span.heading-filter{position:relative;}
input[type="checkbox"].cashback_check:checked + .label_txt::after {
content: "";
font-family: "FontAwesome";
left: 99px;
position: absolute;
top: 5px;
}
.heading-filter::after {
border: 1px solid;
content: "";
display: inline-block;
height: 18px;
width: 18px;
}
input.cashback_check{opacity:0;z-index:3;position:absolute;top:6px;left: 10px;height:30px; width:90%;}
span.heading-filter{position:relative;}
\t input[type="checkbox"].cashback_check:checked + .label-text::after {
\t content: "ok";
\t font-family: "FontAwesome";
\t left:72px;
\t position: absolute;
color:red;
top: 0px;
\t }
\t .heading-filter::after {
\t border: 1px solid #000;
\t content: "";
\t display: inline-block;
\t height: 18px;
\t width: 18px;
\t }
\t input.cashback_check{opacity:0;z-index:3;position:absolute;top:0px;left: 10px;height:30px; width:90%;}
input[type="checkbox"].cashback_check:checked span{background:#ccc;display:block}
<span class="heading-filter">Cashback <input class="cashback_check" value="1" type="checkbox"><label class="label-text"></label></span>
Hast du jQuery oder reines Javascript? – Meloman