[Chapter 4] 4.4 Frame Targets

4.4 Frame Targets

The <frame> tag includes an attribute that allows you to name the frame. A hypertext link in another frame can load its referenced document into the named frame by using the target attribute in the <a> tag. For example:

<frame src="frame.html" name="display_frame">

describes a frame that displays frame.html and is named display_frame. If another frame or window (or even the same frame) contains this link:

<a href="file.html" target="display_frame">

and this link is selected, the file file.html will replace the file frame.html in the frame named display_frame. This is the basic use of targeting frames. A useful example is a book with a table of contents. The table of contents is loaded into a frame that occupies a narrow column on the left side of the browser window. The table of contents contains a list of links to each chapter in the book. Each chapter link targets the frame that occupies the rest of the window. You can then view the chapters while keeping the table of contents available for further navigation.

It can be tedious to specify a target for every hyperlink in your documents, especially when most are targeted at the same window or frame. To alleviate this problem, you can use the target attribute for the <base> tag in the <head> of your document. Adding a target to the <base> tag sets the default target for every hypertext link in the document that does not contain an explicit target attribute.

There are a couple of things to note about the use of targets and named frames:

If a link without a target is contained within a frame, the referenced document will replace the current contents of the same frame if it is selected.
If a link contains a target that does not exist, a new window is opened to display the referenced document, and the window is given the target's name. That window can thus be used by other links that target it.

There are four reserved target names for special document redirection actions, listed below. They all begin with the underscore (_) character. You should not use the underscore character as the first letter of any name that you assign a frame as it will be ignored by the browser.

_blank

A linked document with target="_blank" will always be loaded into a newly opened, unnamed window.

_self

This target value is the default for all <a> tags that do not specify a target, causing the referenced document to be loaded in the same frame or window as the source document. The _self target is redundant and unnecessary unless used in combination with the target attribute of the <base> tag to override the default target value for all the links in the source document.

_parent

The _parent target causes the document to be loaded into the parent window or frameset containing the frame containing the hypertext reference. If the reference is in a window or top-level frame, it is equivalent to the target _self.

_top

This target causes the document to be loaded into the window containing the hypertext link, replacing any frames currently displayed in the window.