How do i multiply checkbox and textfield?

[abim usman]

<h4>Both Product fix price. if checkbox is check and chose quantity automaticaly total</h4> <p class="one">Product

     
    

 Quantity</p> <div class = "checkbox"> <input type="checkbox" name="abim[]" id="tab_price" value="100" onkeyup="AutoCalc(this)">Samsung TV   
 <input type="number" id="tab_quantity" value="0" onkeyup="AutoCalc(this)"><br/> <input type="checkbox" id="mineral_price" name="abim[]" value="200" onkeyup="AutoCalc(this)">SonyVaio TV  
 <input type="number" id="mineral_qunatity" value="0" onkeyup="AutoCalc(this)"><br/><br/>



    Total
  <input type="text" id="total" disabled><br/> </div> <script>
function AutoCalc() {
     var tab_price= 100;
     var mineral_price= 200;         

     var tab_quantity = parseInt(document.getElementById('tab_quantity').value);    
       var mineral_qunatity = parseInt(document.getElementById('mineral_qunatity').value);


       var tota = tab_quantity * tab_price;
       var totag = mineral_qunatity * mineral_price;

       var allTotal =  totalTab + totalAt
        if (isNaN(totalTab)) 
        {
            document.getElementById('total').value = "waiting..";
        }
       document.getElementById('total').value = allTotal;


   }

   </script>