HTML anchors and links_html/css_WEB-ITnose

The difference between A element anchor and link

Anchor and link are both a elements. The only difference is whether there is href attribute.

In Firefox35 and Chrome41, as long as the a element has the name attribute, it is an anchor regardless of whether the name has a value or not. But in IE, if name has no value and no href, it is neither an anchor nor a link.

In all browsers, as long as the a element has the href attribute, it is a link regardless of whether it has a value or not.

Creation and function of anchor

The function of anchor is that when the last part of the URL is #anchorname, the browser will slide the scroll bar so that the anchor appears at the top of the visible window.

Creation method:

Create an a element and set a meaningful name to it;

Do not use the a element, but in On the required element, set a meaningful ID attribute for this element;

A link

Four states of A link

When the A element is used as a link, there are Four pseudo-classes: :link, :hover, :active, :visited, respectively corresponding to the four states of stillness, mouseover, clicked and after clicked.

Download link

Make the href attribute point to a file. As long as the user clicks, it can trigger the browser to download the file, but this is likely to trigger the browser to open a new window.

The A element in HTML5 has an additional download attribute (assign the href value to this attribute). Use this attribute to download files. The browser does not need it. Open a new window to download the file directly.

Specify the window to open the link

The A element has a target attribute. This attribute is not a standard attribute in HTML4 strict mode, but because it is widely used, it has been recognized as a standard attribute in HTML5 property.

The value of the Target attribute should be the name of the frame element, or one of _parent, _top, _self, _blank.

HTML4 standard link opens in a new window

Since target is not a standard attribute in HTML4, if the page complies with W3C standards, it cannot be used directly on the element. But we can use JavaScript to dynamically set the target attribute after the page is loaded.

Notify interested third parties when a link is clicked

This is a new feature added by HTML5. HTML5 adds a ping attribute to the A element . The value of the Ping attribute is a string of space-separated URLs. When the link is clicked, the browser will send a POST request to these URLs, indicating that the link has been clicked.

But now only Chrome36 supports it.

Cache target resources in advance

resource

Link link

The Link link element has no closing tag, so it is placed in the head element.

Load style file

Set site icon

Cache target resources in advance

Others

If you set the href value for a, calling the click method in an old version of Firefox may not trigger a redirection.

In Chrome36, when the dispatchEvent() method is called, the a connection will also be redirected, but not in Firefox30.