$("#rentPeriod").change(function(){
        var cost=1;
        p=this.value;
        let n=document.getElementById("rentNum");
        switch(p) {
            case 1:
                cost = 20000;
                break;
            case 2:
                cost = 2000;
                break;
            case 3:
                cost = 4000;
                break;
            case 4:
                cost = 8000;
                break;
            case 5:
                cost = 14000;
                break;
            case 6:
                cost = 50000;
                break;
            case 7:
                cost = 700000;
                break;
        }
        console.log(cost);
        let output = document.getElementsByTagName("output")[0];
        output.innerHTML = cost;
    })