JSFiddle - React, Tailwind, and code Playground

HTML

<form id="CarSearch" action="" method="post">
 <select name="style" id="Style">
 <option value="" selected>Any Style</option>
 <option value="style/sports-1">Sports</option>
 <option value="style/wagon-3">Wagon</option>
 <option value="style/suv-6">SUV</option>
 </select>

 <select name="make" id="Make">
 <option value="" selected>Any Make</option>
 <option value="make/porsche-3">Porsche</option>
 <option value="make/ford-6">Ford</option>
 <option value="make/volvo-7">Volvo</option>
 </select>
<input id="btnSubmit" type="submit" value="submit"/>
</form>

JavaScript

$("#CarSearch").submit(function (){
    var style = $("#Style").val();
    var make = $("#Make").val();
    var formAction = "";

    if(style != "" && make != ""){
        formAction = "/" + style + "/" + make;
    }else if (style != "" && make == "") {
        formAction = style;
    }else if (style == "" && make != ""){
        formAction = make;
    }else {
       formAction = ""; 
    }
    $("#CarSearch").attr("action", formAction);
    alert('Form Action: ' + $("#CarSearch").attr("action"));
});