jsFiddle无法识别类？
[英]jsFiddle doesn't recognize classes?
问题描述
Originally reported here: Why is my jsfiddle Javascript class not defined? 
最初在这里报道： 为什么我的jsfiddle Javascript类未定义？
However, upon my implementation, I'm seeing similar behavior but none of the answers appear to apply. 但是，在实现过程中，我看到了类似的行为，但似乎没有答案适用。
foo();
baz = new bar();
baz.getMessage();
function foo() {
$('#foo').html("I am foo.");
}
function bar() {
this.message = "I am bar.";
}
bar.prototype = {
getMessage: function() {
$('#bar').html(this.message);
}
};
Fiddle located at: http://jsfiddle.net/eggmatters/qeufnpoj/2/ 小提琴位于： http : //jsfiddle.net/eggmatters/qeufnpoj/2/
Firebug reporting: "TypeError: baz.getMessage is not a function." Firebug报告：“ TypeError：baz.getMessage不是函数。”
2 个解决方案
解决方案1
1 已采纳 2015-02-13 20:58:19
This is because of the location of the bar.prototype . 这是因为bar.prototype的位置。 Specifically because it's after the creation of the instance and call and as such will not be defined yet: 特别是因为它是在创建实例和调用之后，因此尚无法定义：
baz = new bar();
baz.getMessage();
...
bar.prototype = { ... }
Meaning that getMessage() was not yet defined, note that you are using an assignment = , meaning that getMessage() will not be defined until that line is reached in the code. 这意味着尚未定义getMessage() ，请注意，您正在使用Assignment = ，这意味着直到在代码中到达该行才定义getMessage() 。 The solution is to have bar.prototype be defined first: 解决方案是首先定义bar.prototype ：
bar.prototype = { ... }
...
baz = new bar();
baz.getMessage();
解决方案2
1 2015-02-13 20:58:51
First, your JS isn't executing. 首先，您的JS没有执行。 If you change your JS load from "No wrap - in <head>" to "onLoad", it'll run. 如果您将JS负载从“ No wrap-in <head>”更改为“ onLoad”，它将运行。
Or, you can just wrap your JS in an onload function: 或者，您可以将JS包装在onload函数中：
$(function() {
...
}
or 要么
window.onload = function() {
...
}
Second, you need to declare the prototype before you try to execute: 其次，您需要在尝试执行之前声明原型：
foo();
bar.prototype = {
getMessage: function() {
$('#bar').html(this.message);
}
};
baz = new bar();
baz.getMessage();
function foo() {
$('#foo').html("I am foo.");
}
function bar() {
this.message = "I am bar.";
}
JSFiddle: http://jsfiddle.net/5drcuwx5/ JSFiddle： http : //jsfiddle.net/5drcuwx5/
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.