我有一个计算器。对于某些计算，此表单仅在刷新页面时才起作用。加法有效，但乘法仅在刷新后有效。这是为什么？
我不想使用JQuery！
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Card Form</title>
<link href="styles/cardform.css" rel="stylesheet" type="text/css" />
</head>
<body onload='hideTotal()'>
<div id="wrap">
<form action="" id="cardform" onsubmit="return false;">
<div>
<div class="cont_order">
<fieldset>
<legend>Check Quotes</legend>
<label>Size Of the Card</label>
<label>Width in cm: </label> <input type="text" id="width" />
<label>Height in cm: </label> <input type="text" id="height" />
<br/>
<br/>
<label class='radiolabel'><input type="radio" name="selectedcard1" value="Round13" onclick=""/>Standard</label>
<label class='radiolabel'><input type="radio" name="selectedcard1" value="Round14" onclick="" />Toughened</label><br/>
<br/>
<label>Card: </label>
<label class='radiolabel'><input type="radio" name="selectedcard2" value="Round17" onclick=""/>Clear</label>
<label class='radiolabel'><input type="radio" name="selectedcard2" value="Round18" onclick="" />Frosted</label>
<label class='radiolabel'><input type="radio" name="selectedcard2" value="Round19" onclick="" />Leaded</label>
<label class='radiolabel'><input type="radio" name="selectedcard2" value="Round20" onclick="" />White Bar</label>
<br/>
<label>Frame: </label>
<label class='radiolabel'><input type="radio" name="selectedcard3" value="Round21" onclick=""/>uPVC</label>
<label class='radiolabel'><input type="radio" name="selectedcard3" value="Round22" onclick="" />Metal</label>
<label class='radiolabel'><input type="radio" name="selectedcard3" value="Round23" onclick=""/>Wood</label>
<br/>
<input type="submit" value="Calculate" onClick="calculateTotal()" />
<INPUT TYPE="reset" VALUE="RESET" onClick="resetIt()" />
<div id="totalPrice"></div>
</fieldset>
</div>
</div>
</form>
</div>
<!--End of wrap-->
</body>
<script>
var size1 = document.getElementById("width").value;
var size2 = document.getElementById("height").value;
var total_size = ((size1 * size2) / 10000);
var card_prices = new Array();
card_prices["Round13"] = (total_size * 67);
card_prices["Round14"] = (total_size * 87);
card_prices["Round17"] = (total_size * 0.05);
card_prices["Round18"] = (total_size * 0.65);
card_prices["Round19"] = (total_size * 0.85);
card_prices["Round20"] = (total_size * 0.95);
function getCardSizePrice2() {
var cardSizePrice = 0;
//Get a reference to the form id="cardform"
var theForm = document.forms["cardform"];
//Get a reference to the card the user Chooses name=selectedCard":
var selectedCard1 = theForm.elements["selectedcard1"];
//Here since there are 4 radio buttons selectedCard.length = 4
//We loop through each radio buttons
for (var i = 0; i < selectedCard1.length; i++) {
//if the radio button is checked
if (selectedCard1[i].checked) {
//we set cardSizePrice to the value of the selected radio button
//i.e. if the user choose the 8" card we set it to 25
//by using the card_prices array
//We get the selected Items value
//For example card_prices["Round8".value]"
cardSizePrice = card_prices[selectedCard1[i].value];
//If we get a match then we break out of this loop
//No reason to continue if we get a match
break;
}
}
//We return the cardSizePrice
return cardSizePrice;
}
function getCardSizePrice3() {
var cardSizePrice = 0;
//Get a reference to the form id="cardform"
var theForm = document.forms["cardform"];
//Get a reference to the card the user Chooses name=selectedCard":
var selectedCard = theForm.elements["selectedcard2"];
//Here since there are 4 radio buttons selectedCard.length = 4
//We loop through each radio buttons
for (var i = 0; i < selectedCard.length; i++) {
//if the radio button is checked
if (selectedCard[i].checked) {
cardSizePrice = card_prices[selectedCard[i].value];
break;
}
}
return cardSizePrice;
}
function getCardSizePrice4() {
card_prices["Round21"] = 2;
card_prices["Round22"] = 5;
card_prices["Round23"] = 5;
var cardSizePrice = 0;
//Get a reference to the form id="cardform"
var theForm = document.forms["cardform"];
//Get a reference to the card the user Chooses name=selectedCard":
var selectedCard = theForm.elements["selectedcard3"];
//Here since there are 4 radio buttons selectedCard.length = 4
//We loop through each radio buttons
for (var i = 0; i < selectedCard.length; i++) {
//if the radio button is checked
if (selectedCard[i].checked) {
cardSizePrice = card_prices[selectedCard[i].value];
break;
}
}
return cardSizePrice;
}
var divobj = document.getElementById('totalPrice');
function calculateTotal() {
//Here we get the total price by calling our function
//Each function returns a number so by calling them we add the values they return together
var cardPrice = getCardSizePrice2() + getCardSizePrice3() + getCardSizePrice4();
//display the result
divobj.style.display = 'block';
divobj.innerHTML = "Total Price For the Card: £" + " " + cardPrice;
displaytotal(divobj);
}
function displaytotal() {
}
function hideTotal() {
var divobj = document.getElementById('totalPrice');
divobj.style.display = 'none';
}
function resetIt() {
var divobj = document.getElementById('totalPrice');
divobj.style.display = 'none';
}
</script>
</html>最佳答案
我们了解到您已经找到了问题（我相信这与以下事实有关：您已使用提交按钮设置了代码，并且在触发页面加载事件后立即计算了总数，而不是单击总计按钮）。
但是，除此之外，您可能仍需要非常仔细地查看此答案，因为您拥有的代码在许多方面都太糟糕了：
HTML：
您的HTML使用不正确。您没有使用<label>
或<fieldset>元素正确。
因为您实际上只需要一个实际上并不需要的计算器
在任何地方提交数据，您都不需要提交按钮。
您正在使用内联HTML事件处理程序（onsubmit，onclick，
等），不应该使用它，因为：
他们创建难以理解的“意大利面条代码”，并导致
代码重复。
它们导致全局事件处理包装函数被隐式包含
围绕您提供的属性值创建的this对象的绑定不能按预期方式工作。
他们不遵循W3C Standards for Event Handling
JavaScript：
您正在为要准备的HTML元素设置变量
在各种功能中使用，这意味着每次
函数运行时，它必须重新重新扫描文档以查找
元素。
当对象更合适时，您正在使用数组。
您实际上编写了3次相同的函数，而不仅仅是
拥有一次并传递一个参数，该参数可以随您而改变
需要它。
这是一个遵循最佳实践，语义且不会重复的清理版本。有关详细信息，请参见嵌入式注释。
window.addEventListener("DOMContentLoaded", function(){
// Get references to DOM elements that we'll need access to just once. Don't set variables
// up to store their values at first. Set the variable to the elmement. That way, you can
// go back to the element as often as you need to in order to get any property value you
// like, without having to re-scan the document for it all over again:
var size1 = document.getElementById("width");
var size2 = document.getElementById("height");
var divObj = document.getElementById('totalPrice');
var theForm = document.getElementById("cardform");
var selectedCard1 = theForm.querySelectorAll("[name=selectedcard1]");
var selectedCard2 = theForm.querySelectorAll("[name=selectedcard2]");
var selectedCard3 = theForm.querySelectorAll("[name=selectedcard3]");
var calc = document.querySelector("input[type=button]");
var res = document.querySelector("input[type=reset]");
// Set up event handlers for various DOM elements:
calc.addEventListener("click", calculateTotal);
res.addEventListener("click", reset);
// Create a storage mechanism that holds "keys" and associated "values"
// Arrays can only do this with sequential numeric indexes. Objects, do it
// with string property names.
var card_prices = {};
// No reason to have 3 functions that all do basically the same thing but only
// to different objects. Just have one function that accepts a reference to the
// radiobuttons it needs to work with
function getCardSizePrice(cards){
var cardSizePrice = 0;
// Loop through each radio button in the passed in group
for(var i = 0; i < cards.length; i++) {
//if the radio button is checked
if(cards[i].checked) {
// Lookup the value of the selected radio button in our object and get the
// associate property value
cardSizePrice = card_prices[cards[i].value];
// No reason to continue if we get a match
break;
}
}
// We return the cardSizePrice
return cardSizePrice;
}
function calculateTotal() {
// You didn't have the following code in this funciton, so it was running immediately
// when the page loaded.
// Remember, values that you take out of form elements are strings!
// If you want to treat them as numbers, you should explicitly convert them
// to numbers first:
var s1 = parseFloat(size1.value);
var s2 = parseFloat(size2.value);
var total_size = (s1 * s2) / 10000;
// Set all the property values
card_prices["Round13"] = total_size * 67,
card_prices["Round14"] = total_size * 87,
card_prices["Round17"] = total_size * .05,
card_prices["Round18"] = total_size * .65,
card_prices["Round19"] = total_size * .85,
card_prices["Round20"] = total_size * .95,
card_prices["Round21"] = 2;
card_prices["Round22"] = 5;
card_prices["Round23"] = 5;
// Here we get the total price by calling our function
// Each function returns a number so by calling them we add the values they return together
var cardPrice = getCardSizePrice(selectedCard1) +
getCardSizePrice(selectedCard2) +
getCardSizePrice(selectedCard3);
displayTotal(cardPrice);
}
function displayTotal(price) {
// display the result
divObj.classList.remove("hidden");
divObj.innerHTML = "Total Price For the Card: £" + " " + price.toFixed(2);
}
function reset(){
divObj.innerHTML = "";
}
});#totalPrice { background-color:#ff0; } // Default style for element
#panel { margin-top: 1em;}
fieldset { margin-bottom:1em; }<body>
<div id="wrap">
<form action="#" id="cardform">
<div class="cont_order">
<h1>Check Quotes</h1>
<!-- Fieldsets are for logical grouping of form elements. While they do have a
visual component to them, they are primarially for accessibility for
visually impaired. -->
<fieldset>
<legend>Size Of the Card</legend>
<!-- Labels associate with form elements via the "for" attribute and the target
element's "id" attribute. They aren't just for displaying random text.
They are a key aspect of designing for accessibility. You can click/touch the
label and activate the associated form element. -->
<label for="width">Width in cm:</label> <input type="text" id="width">
<label for="height">Height in cm:</label> <input type="text" id="height">
<br><br>
<input type="radio" name="selectedcard1" id="selectedcard1a" value="Round13">
<label for="selectedcard1a" class='radiolabel'>Standard</label>
<input type="radio" name="selectedcard1" id="selectedcard1b" value="Round14">
<label for="selectedcard1b" class='radiolabel'>Toughened</label><br>
</fieldset>
<fieldset>
<legend>Card</legend>
<input type="radio" name="selectedcard2" id="selectedcard2a" value="Round17">
<label for="selectedcard2a" class='radiolabel'>Clear</label>
<input type="radio" name="selectedcard2" id="selectedcard2b" value="Round18">
<label for="selectedcard2b" class='radiolabel'>Frosted</label>
<input type="radio" name="selectedcard2" id="selectedcard2c" value="Round19">
<label for="selectedcard2c" class='radiolabel'>Leaded</label>
<input type="radio" name="selectedcard2" id="selectedcard2d" value="Round20">
<label for="selectedcard2d" class='radiolabel'>White Bar</label>
</fieldset>
<fieldset>
<legend>Frame</legend>
<input type="radio" name="selectedcard3" id="selectedcard3a" value="Round21">
<label for="selectedcard3a" class='radiolabel'>uPVC</label>
<input type="radio" name="selectedcard3" id="selectedcard3b" value="Round22">
<label for="selectedcard3b" class='radiolabel'>Metal</label>
<input type="radio" name="selectedcard3" id="selectedcard3c" value="Round23">
<label for="selectedcard3c" class='radiolabel'>Wood</label>
</fieldset>
<div id="panel">
<input type="button" value="Calculate">
<input type="reset" value="Reset">
<div id="totalPrice"></div>
</div>
</div>
</form>
</div>关于javascript - 为什么只在刷新后才发生乘法？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/42472227/