我们可以像while(condition);C编程一样放分号吗？如果while(condition);有效,这是什么意思？
我是HTML的新手,我正在尝试使用HTML和Javascript制作邮资计算器,如果用户需要快递,用户输入包裹的名称权重.所有选项都会影响价格,但由于某些原因,我的变量快递成本被固定在5英镑.
<!DOCTYPE html>
<html>
<head>
<title>Postage Calculator</title>
<script>
function calCost() {
console.log("Invoked calCost()")
document.getElementById('displayName').innerHTML = document.getElementById("name").value;
var expressCost = 0;
if (document.getElementById('express').checked) ; //always checked
{
console.log("yup"); // this was to test if it was staying checked which it does.
expressCost = 5;
}
if (document.getElementById('r1').checked) {
document.getElementById('displayCost').innerHTML = "\u00A3" + (2 * document.getElementById("weight").value + expressCost);
}
else if (document.getElementById('r2').checked) {
document.getElementById('displayCost').innerHTML = "\u00A3" + (10 * document.getElementById("weight").value + expressCost);
}
else {
document.getElementById('displayCost').innerHTML = "\u00A3" + (5 * document.getElementById("weight").value …