已废弃
该特性已经从 Web 标准中删除，虽然一些浏览器目前仍然支持它，但也许会在未来的某个时间停止支持，请尽量不要使用该特性。

The `fontsize()` method creates a `<font>` HTML element that causes a string to be displayed in the specified font size.

Usage note: The <font> element has been removed in HTML5 and shouldn't be used anymore. Instead web developers should use CSS properties.

## 语法

    str.fontsize(size)

### 参数

`size`
  An integer between 1 and 7, a string representing a signed integer between 1 and 7.

### 返回值

A string containing a `<font>` HTML element.

## 描述

When you specify size as an integer, you set the font size of `str` to one of the 7 defined sizes. When you specify `size` as a string such as "-2", you adjust the font size of `str` relative to the size set in the `<basefont>` tag.

## 示例

### `使用fontsize()方法`

The following example uses string methods to change the size of a string:

    var worldString = 'Hello, world';

    console.log(worldString.small());     // <small>Hello, world</small>
    console.log(worldString.big());       // <big>Hello, world</big>
    console.log(worldString.fontsize(7)); // <font size="7">Hello, world</fontsize>

With the `element.style` object you can get the element's `style` attribute and manipulate it more generically, for example:

    document.getElementById('yourElemId').style.fontSize = '0.7em';

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript 2015 (6th Edition, ECMA-262) String.prototype.fontsize | Standard | Initial definition. Implemented in JavaScript 1.0. Defined in the (normative) Annex B for Additional ECMAScript Features for Web Browsers.
ECMAScript Latest Draft (ECMA-262) String.prototype.fontsize | Draft | Defined in the (normative) Annex B for Additional ECMAScript Features for Web Browsers.

## 浏览器兼容性

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

- Desktop
- Mobile

Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari
--- | --- | --- | --- | --- | ---
Basic support | (Yes) | 1.0 (1.7 or earlier) | (Yes) | (Yes) | (Yes)

Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile
--- | --- | --- | --- | --- | --- | ---
Basic support | (Yes) | (Yes) | 1.0 (1.0) | (Yes) | (Yes) | (Yes)

## 相关链接

- `String.prototype.big()`
- `String.prototype.small()`