Javascript 为什么我能'；无法获取BAC的返回值？

//尝试获取我的BAC级别输出

function formbac(){
//values
var weight = document.getElementById("weight").value;
var beer = document.getElementById("beer" * .54).value;
var wine = document.getElementById("wine" * .6).value;
var shots = document.getElementById("shots" * .6).value;
var time= document.getElementById("time").value;
var BAC = 0;

//计算
var BAC=（（啤酒+葡萄酒+酒杯*7.5）/（重量*0.68））-（0.015*次）；
//小数点
var BAC=数学四舍五入（BAC*100）/100；
//输出
var BAC=document.getElementById（BAC）.value；
}

您的输出应该是另一种方式：

// calculations
var BAC = ((beer + wine + shots * 7.5) / (weight * .68)) - (0.015 * time);

//decimal round
var BAC = math.round(bac*100)/100;

//output
var BAC = document.getElementById(BAC).value;

}
</script>

</body>



</html>

此外，您试图在

document.getElementById

内部执行的所有乘法都应该在外部执行。例如：

//output
document.getElementById('BAC').value = BAC;

试试这句话

var beer = document.getElementById("beer").value  * .54;

---

根据您的代码，您的输出将是输入控件的值。

document.getElementById（“shots”*.6）。值

与您认为的不一样。@Mathletics它应该适用于

：-）仍然无法获取返回值。我可以获取元素并将其显示在文本框中，但它只会闪烁然后消失。如何使元素保持在BAC表单框中？？

// calculations
var BAC = ((beer + wine + shots * 7.5) / (weight * .68)) - (0.015 * time);

//decimal round
var BAC = math.round(bac*100)/100;

//output
var BAC = document.getElementById(BAC).value;

}
</script>

</body>



</html>

//output
document.getElementById('BAC').value = BAC;

var beer = document.getElementById("beer").value  * .54;

document.getElementById("BAC").value = BAC; //notice "BAC" instead of BAC, you're trying to grab the element that doesn't exist

// calculations
var BAC = ((beer + wine + shots * 7.5) / (weight * .68)) - (0.015 * time);

//decimal round
var BAC = math.round(bac*100)/100; //override above value 

//output
var BAC = document.getElementById(BAC).value; //override above value