function product(input){  
     if (toString.call(input) !== "[object Array]")  
        return false;  
        
             var total   =   1;  
        
           for(var i=0;i<input.length;i++){  
                   if(isNaN(input[i])){  
                     continue;  
                   }  
                    total   *=  Number(input[i]);  
                }  
              return total;  
            }  
    console.log(product([1,2,3]));  
    console.log(product([100,-200,3]));  
    console.log(product([1,2,'a',3]));