[HTML] 2-5 <h1> to <h6>－給你魚竿

HTML用<h1>到<h6>來定義標頭
Browsers會自動在標題上面加一些空白
Search engines會根據你的headings來當作你網頁的index
應該要依據重要層度來使用<h1>到<h6>
而不是拿來當作粗細或大字來使用

Browser Support
主流皆有support

HTML5之後不支援align屬性, 要改用CSS
支援Global Attributes
支援Event Attributes

Default CSS Settings

h1 {
    display: block;
    font-size: 2em;
    margin-top: 0.67em;
    margin-bottom: 0.67em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

h2 {
    display: block;
    font-size: 1.5em;
    margin-top: 0.83em;
    margin-bottom: 0.83em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

h3 {
    display: block;
    font-size: 1.17em;
    margin-top: 1em;
    margin-bottom: 1em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

h4 {
    display: block;
    margin-top: 1.33em;
    margin-bottom: 1.33em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

h5 {
    display: block;
    font-size: .83em;
    margin-top: 1.67em;
    margin-bottom: 1.67em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

h6 {
    display: block;
    font-size: .67em;
    margin-top: 2.33em;
    margin-bottom: 2.33em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

1. 官網http://www.w3schools.com/tags/tag_hn.asp