获取总和并将其打印到一个元素

Question

我如何从函数传递值？有没有办法从函数中获取结果。我制作了一个关于订购披萨的简单程序。披萨有3种选择，大小有3种选择（小，中，大），还有一些浇头选择，价格不同。

所以我认为我可以通过将所有选择的选项值推送到一个数组然后使用“减少”方法来获得总数来获得总数。或者还有其他解决方案吗？

 var subTotal=[];

function pizzaChoice(menuId) {

//  push result to subTotal array

}

function pickSize(size) {

//  push result to subTotal array

}

function pickTopping(topping) {

    //  push result to subTotal array

}

function calc(){

// add up all using reduce method 

}

Answer 1

你的问题太宽泛，但我会定义所有价格，而不是计算是一个简单的步骤：var prices = {&nbsp; &nbsp; 'vegetariana': {&nbsp; &nbsp; &nbsp; &nbsp; 's': 8,&nbsp; &nbsp; &nbsp; &nbsp; 'm': 10,&nbsp; &nbsp; &nbsp; &nbsp; 'l': 12&nbsp; &nbsp; },&nbsp; &nbsp; 'cheese': {&nbsp; &nbsp; &nbsp; &nbsp; 's': 9,&nbsp; &nbsp; &nbsp; &nbsp; 'm': 11,&nbsp; &nbsp; &nbsp; &nbsp; 'l': 14&nbsp; &nbsp; },&nbsp; &nbsp; 'margherita': {&nbsp; &nbsp; &nbsp; &nbsp; 's': 8.3,&nbsp; &nbsp; &nbsp; &nbsp; 'm': 10.5,&nbsp; &nbsp; &nbsp; &nbsp; 'l': 13&nbsp; &nbsp; },};function getPizzaPrice(name, size) {&nbsp; &nbsp; return prices[name][size];};function displayPrice() {&nbsp; &nbsp; var pizzaName = document.getElementById("name").value;&nbsp; &nbsp; var pizzaSize = document.getElementById("size").value;&nbsp; &nbsp; var pizzaPrice = getPizzaPrice(pizzaName, pizzaSize);&nbsp; &nbsp; document.getElementById("result").innerHTML = pizzaPrice;};document.getElementById("name").onchange = displayPrice;document.getElementById("size").onchange = displayPrice;displayPrice();<select id="name">&nbsp; &nbsp; <option value="vegetariana">Vegetariana</option>&nbsp; &nbsp; <option value="cheese">Cheese</option>&nbsp; &nbsp; <option value="margherita">Margherita</option></select><select id="size">&nbsp; &nbsp; <option value="s">Small</option>&nbsp; &nbsp; <option value="m">Medium</option>&nbsp; &nbsp; <option value="l">Large</option></select><p>Price: <span id="result"></span></p>也在JSFiddle上。请注意，有很多方法可以做到这一点。

Answer 2

获取函数结果的最基本方法是返回它。请参见下面的示例：function [functionName]([parameters]){&nbsp; &nbsp; // do things&nbsp; &nbsp; return [your result];}方括号里的东西是占位符值，随便替换。