function calc_bmi(f) {
    var bmi, my_height, my_weight;

    my_height = eval(f.height.value) / 100;
    my_weight = eval(f.weight.value);
    bmi = my_weight / my_height / my_height;
    f.bmi.value = bmi;
    f.ave.value = 22 * my_height * my_height;
    if (bmi < 20) {
        f.result.value = "やせ"
    }
    else if (bmi < 24) {
        f.result.value = "正常"
    }
    else if (bmi < 26.5) {
        f.result.value = "やや肥満"
    }
    else {
        f.result.value = "肥満"
    }
}