Javascript做时循环问题
[英]Javascript do-while looping problems
问题描述
I need help with looping the javascript in a do/while statement loop. 
我需要在do / while语句循环中循环javascript的帮助。
The problems I am having is that I don't want to display the incorrect information in my table when entering an invalid product, but it does display in the document.write. 我遇到的问题是，当我输入无效的产品时，我不想在表格中显示不正确的信息，但是它确实显示在document.write中。 I need help in order to make sure that the incorrect information won't be displayed. 我需要帮助以确保不会显示不正确的信息。
Also, when I hit "ok" to add more to my order, it doesn't loop it but merely displays the document.write. 另外，当我单击“确定”以向订单中添加更多内容时，它不会循环播放，而只会显示document.write。 I want it to loop if you hit the "ok" button. 如果您单击“确定”按钮，我希望它循环播放。
Thank you for the help. 感谢您的帮助。
Here is the code: 这是代码：
<html>
<head><title>Javascript Assignment 3: Daniel Weiner</title>
</head>
<body bgcolor="brown">
<h1 align="center">Big Ben's Burgers-eCommerce</h1>
<table border="1" width="100%" height="450px" bgcolor="gray"><tr>
<th align="center">Product/Service</th>
<th align="center">Price</th>
<th align="center">Discount</th>
</tr>
<tr bgcolor="orange">
<td align="center"><font size="3">Hamburger
<br>
<br>
<a href="http://www.mcdonalds.com/us/en/food/product_nutrition.sandwiches.256.Hamburger.html" target="_blank">Classic Hamburger</a>
<td align="right" bgcolor="orange"><font size="3">$8.00</font></td>
<td align="center" bgcolor="orange"><font size="3">.10</font></td>
</tr>
<tr bgcolor="orange">
<td align="center"><font size="3">Cheeseburger
<br>
<br>
<a href="http://www.mcdonalds.com/us/en/food/product_nutrition.sandwiches.284.cheeseburger.html" target="_blank">Classic Cheeseburger </a>
</font></td>
<td align="right" bgcolor="orange"><font size="3">$9.00</font></td>
<td align="center" bgcolor="orange"><font size="3">.05</font></td>
</tr>
<tr bgcolor="orange">
<td align="center"><font size="3">Soda
<br>
<br>
<a href="http://www.mcdonalds.com/us/en/food/full_menu/beverages.html" target="_blank">Fabulous Drinks</a>
</font></td>
<td align="right" bgcolor="orange"><font size="3">$2.00
</font></td>
<td align="center" bgcolor="orange"><font size="3"> .07</font></td>
</tr>
<tr bgcolor="red">
<td align="center"><font size="3"> French Fries
<br>
<br>
<a href="http://www.mcdonalds.com/us/en/food/product_nutrition.snackssides.120.small-french-fries.html" target="_blank"> Fries</a>
</font></td>
<td align="right" bgcolor="red"><font size="3"> $4.00</font></td>
<td align="center" bgcolor="red"><font size="3">.15</font></td>
</table>
<script type="text/javascript">
/*Daniel Weiner, Fengpeng Yuan, Javascript 2, Nov 4,2011*/
var username;
var bprice= 8;
var chprice= 9;
var sprice= 2;
var fprice= 4;
var price= 0;
var a;
var b;
var product= "hamburger, cheeseburger, soda, fries";
var quantity =0;
var total;
var cost = 0;
var discount= 0;
do{
username =prompt("Welcome to Big Ben's Burgers. Please enter your name.", "");
alert("Hello " + username+". Please look through our available products and services before placing your order.","");
product=prompt("What do you want?","");
quantity =1*prompt("How many of " +product+ " would you like?");
if (product == "hamburger")
{
price = bprice;
discount = .1;
}
else if (product == "cheeseburger")
{
price = chprice;
discount = .05;
}
else if (product == "soda")
{
price = sprice;
discount = .07;
}
else if (product == "fries")
{
price = fprice;
discount = .15;
}
else{
alert("Sorry, " +username+ " Your item not found.");
}
cost=price*quantity
discount=price*discount*quantity
total=cost-discount
document.write("The cost of buying " +quantity+ " of " +product+ " is $" +cost+ ".<br/>");
document.write("This discount for this purchase is $" +discount+ ".<br/>");
}while(a==false)
a = confirm("Do you want to place another order?");
(b==false)
document.write("Thank you for placing an order with us, " +username+ ".<br/>");
document.write("The total order cost is $" +total+ ".");
</script>
</body>
</html>
3 个解决方案
解决方案1
0 2011-11-03 20:43:45
对于问题的第二部分，您必须在循环中使用下面的语句
a = confirm("Do you want to place another order?");
解决方案2
0 2011-11-03 20:51:20
It looks like you aren't conditioning the part that outputs the result on whether or not a valid product was selected. 似乎您没有在根据是否选择了有效产品来调节输出结果的零件。 You need something like the following; 您需要以下内容：
do{
....
productValid = false;
if (product == "hamburger")
{
price = bprice;
discount = .1;
productValid = true;
}
else if (product == "cheeseburger")
{
price = chprice;
discount = .05;
productValid = true;
}
else if (product == "soda")
{
price = sprice;
discount = .07;
productValid = true;
}
else if (product == "fries")
{
price = fprice;
discount = .15;
productValid = true;
}
else{
alert("Sorry, " +username+ " Your item not found.");
}
if(productValid){
cost=price*quantity
discount=price*discount*quantity
total=cost-discount
document.write("The cost of buying " +quantity+ " of " +product+ " is $" +cost+ ".<br/>");
document.write("This discount for this purchase is $" +discount+ ".<br/>");
}
else
{
document.write("No valid product selected<br>");
}
a = confirm("Do you want to place another order?");
}while(a==true)
解决方案3
0 2011-11-03 20:52:47
You're re-iterating the loop if the user hits cancel . 如果用户点击cancel那么您将重复循环。 Change while(a==false) to while(a==true) or simply while(a) 将while(a==false)更改为while(a==true)或简单地while(a)
Also put the line 还把线
a = confirm("Do you want to place another order?");
as the last line in your loop, instead of the line after. 如在循环的最后一行，而不是以后就行了。
You can set a flag var that lets you know if the item was found or not and check it at the end of your loop to avoid displaying data for non-existing items: 您可以设置一个标志var，让您知道是否找到了该项目，并在循环结束时对其进行检查，以避免显示不存在的项目的数据：
<script type="text/javascript">
/*Daniel Weiner, Fengpeng Yuan, Javascript 2, Nov 4,2011*/
var username;
var bprice= 8;
var chprice= 9;
var sprice= 2;
var fprice= 4;
var price= 0;
var a;
var b;
var product= "hamburger, cheeseburger, soda, fries";
var quantity =0;
var total;
var cost = 0;
var discount= 0;
var flag;
do{
flag = true; //assume found unless otherwise
username =prompt("Welcome to Big Ben's Burgers. Please enter your name.", "");
alert("Hello " + username+". Please look through our available products and services before placing your order.","");
product=prompt("What do you want?","");
quantity =1*prompt("How many of " +product+ " would you like?");
if (product == "hamburger")
{
price = bprice;
discount = .1;
}
else if (product == "cheeseburger")
{
price = chprice;
discount = .05;
}
else if (product == "soda")
{
price = sprice;
discount = .07;
}
else if (product == "fries")
{
price = fprice;
discount = .15;
}
else{
alert("Sorry, " +username+ " Your item not found.");
flag = false;
}
if(flag){
cost=price*quantity
discount=price*discount*quantity
total=cost-discount
document.write("The cost of buying " +quantity+ " of " +product+ " is $" +cost+ ".<br/>");
document.write("This discount for this purchase is $" +discount+ ".<br/>");
}
a = confirm("Do you want to place another order?");
}while(a);
alert('goodbye');
</script>
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.