我目前正在使用 OOP 来显示烹饪食谱。一切都很好，除了我使用该document.write方法时。当显示price. 这是我的代码：<html> <body> <p id = "p"></p><script>function Recipe(name, ingredients, price) { this.name = name; this.ingredients = ingredients; this.price = price;}function describe(name, ingredients, price) { document.write("<h2> Recipe name: " + name + "</h2> Ingredients: " + ingredients + "<br />Price: " + price);}var instantRamen = new Recipe("Ramen", "Ramen noodles, hot water, salt, (optional) green pepper", "$2.00");var Bagel = new Recipe("Ham and cheese bagel", "Bagel (preferably an everything bagel), ham, cheese (of any type), pepper (just a little)", "$6.00");document.write(describe(instantRamen.name, instantRamen.ingredients, instantRamen.price));document.write(describe(Bagel.name, Bagel.ingredients, Bagel.price));</script></body></html>预期结果将类似于“食谱名称：拉面（换行）配料：拉面、热水、盐、（可选）青椒（换行）价格：2.00 美元”，但价格变为“2.00 美元未定义”。其他一切都有效。我最初认为创建instantRamenandBagel实例时有问题，所以我尝试更改一些语法但无济于事。
3 回答
桃花长相依
TA贡献1860条经验 获得超8个赞
您可以return像这样使用您的功能。
因为您没有返回任何值。那西undefined
function Recipe(name, ingredients, price) {
this.name = name;
this.ingredients = ingredients;
this.price = price;
}
function describe(name, ingredients, price) {
return "<h2> Recipe name: " + name + "</h2> Ingredients: " + ingredients + "<br />Price: " + price;
}
var instantRamen = new Recipe("Ramen", "Ramen noodles, hot water, salt, (optional) green pepper", "$2.00");
var Bagel = new Recipe("Ham and cheese bagel", "Bagel (preferably an everything bagel), ham, cheese (of any type), pepper (just a little)", "$6.00");
document.write(describe(instantRamen.name, instantRamen.ingredients, instantRamen.price));
document.write(describe(Bagel.name, Bagel.ingredients, Bagel.price));
<html>
<body>
<p id = "p"></p>
</body>
</html>
我已经删除document.write了return字符串。
天涯尽头无女友
TA贡献1831条经验 获得超9个赞
问题是你在函数describe内部调用document.write函数。它写undefined因为 describe 什么都不返回。
发生的事情是：首先，describe函数在文档中写入 html 文本。然后，您尝试describe在文档中编写函数的返回。
您不需要将describe函数放在里面，document.write.只需使用您想要的参数调用它即可。
慕尼黑5688855
TA贡献1848条经验 获得超2个赞
现在它的工作
<html>
<body>
<p id = "p"></p>
<script>
function Recipe(name, ingredients, price) {
this.name = name;
this.ingredients = ingredients;
this.price = price;
}
function describe(name, ingredients, price) {
document.write("<h2> Recipe name: " + name + "</h2> Ingredients: " + ingredients + "<br />Price: " + price );
}
var instantRamen = new Recipe("Ramen", "Ramen noodles, hot water, salt, (optional) green pepper", "$2.00");
var Bagel = new Recipe("Ham and cheese bagel", "Bagel (preferably an everything bagel), ham, cheese (of any type), pepper (just a little)", "$6.00");
//edited
describe(instantRamen.name, instantRamen.ingredients, instantRamen.price);
describe(Bagel.name, Bagel.ingredients, Bagel.price);
document.getElementById("p").innerHTML = "Your browser version is " + navigator.appVersion;
</script>
</body>
</html>
添加回答
举报
0/150
提交
取消