JS 函数的声明方式参数注意返回函数

2017-08-13 11:20:16 Albin Wong 451

## 函数的声明方式
### 第一种 可实现函数优先加载的
```javascript
func();
var func = 100;
function func() {
    alert('第一种声明方式');
}
func();
```
### 第二种 匿名 函数名不能跟变量名重复
```javascript
func_2();
var func_2 = function() {
    alert('第二种声明方式');
}
func_2(); // JS调用匿名函数只在声明函数之后
```
### 第三种 
```javascript
var func_3 = new Function('x','y','alert(x+y)');
func_3(1,3); // 4

//函数调用
func();  //直接调用
//赋值给一个变量
var res = func();
alert(res); // 在函数内部如无return 手动返回一个值的话,默认是undefined
<div style="width:200px;height:200px;background:red" onclick="func_2()"></div> // 事件调用
```

### 参数注意
```javascript
// 不要加初始值 IE浏览器不兼容
function func($a, $b = 10) {
    alert($a+$b);
}

(3) Comments

John Doe- Reply

February 26, 2013 at 1:18 pm
- saqib sarwar- Reply
  
  February 26, 2013 at 1:20 pm
  
  Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Typi non habent claritatem insitam; est usus legentis in iis qui facit eorum claritatem. Investigationes demonstraverunt lectores legere me lius quod ii legunt saepius. Claritas est etiam processus dynamicus, qui sequitur mutationem consuetudium lectorum. Mirum est notare quam littera gothica, quam nunc putamus parum claram, anteposuerit litterarum formas humanitatis per seacula quarta decima et quinta decima. Eodem modo typi, qui nunc nobis videntur parum clari, fiant sollemnes in futurum.
John Doe- Reply

February 26, 2013 at 1:27 pm

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum.

Your email address will not be published. Required fields are marked *

Name *

Email *

Website

Comment

You can use these HTML tags and attributes <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

JS 函数的声明方式 参数注意 返回函数

(3) Comments

John Doe- Reply

saqib sarwar- Reply

John Doe- Reply