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External Linking, Address Outside Current Web Site

Syntax
See Also
Description
uri
linkingtext
File URI
User Text
Other URIs
White Space
Checking Links
frame, Deprecated 2006-07-07
     Display Frame

Syntax
$href%uri%$$
 $href%uri%linkingtext%$$
 $href%uri%linkingtext%frame%$$
See Also
image_link , keyword list , cref

Description
This command is used to specify a link to an address on the internet that is external to the current web site. (It may however be in the same directory.) The text after the $href and before the $$ is a delimiter sequence where % can be any character that is not a letter.

uri
The characters in uri are the Universal Resource Identifier that specifies the internet address corresponding to the href command. Leading and trailing white space in uri is ignored.

linkingtext
If linkingtext is present in the delimiter sequence, it specifies the text that the user will see for the link. If linkingtext is not present, the user will see uri for the link. Leading and trailing white space in link is ignored.

File URI
The following input 
 
     $href%http://www.w3.org/tr/rec-html32.html%$$
links the text http://www.w3.org/tr/rec-html32.html to the corresponding internet file. The result is the following link
      http://www.w3.org/tr/rec-html32.html

User Text
The following input 
 
     $href%http://www.w3.org/tr/rec-html32.html%HTML 3.2%$$
links the text HTML 3.2 to the file specified by 
 
     http://www.w3.org/tr/rec-html32.html
The result is the following link
      HTML 3.2

Other URIs
You can reference an anchor within a page using the href command. For example 
 
     $href%http://www.w3.org/tr/MathML2/chapter1.html#intro_goals%$$
results in the following link
      http://www.w3.org/tr/MathML2/chapter1.html#intro_goals
In general, the characters between the first and second delimiter specify an arbitrary URI on the internet. For example it can reference a mailto command or a ZIP file.

White Space
Leading and trailing white space in uri , link and frame is ignored. This is useful when these arguments are long. For example, 
 
     $href%http://www.w3.org/tr/MathML2/chapter1.html#intro_goals
          %Design Goals of MathML
     %$$
results in the following link
      design goals of MathML .

Checking Links
OMhelp does not check that the internet addresses specified by your href commands are valid. If you use the -debug option on the command line , OMhelp will generate a section to aid you in checking that the these addresses are valid. The cross reference tag for this automatically generated section is _external. You can see the corresponding section for this web site by selecting the following link .

frame, Deprecated 2006-07-07
If frame is present, it is an integer that specifies the frame with in the current browser window that the result of the link is displayed in. If no such frame exists, a separate browser window is used to display the result of the link. If frame is less than one or greater than the number of frames in the current browser window, a separate window is used to display the result of the link. Leading and trailing white space in frame is ignored.

Display Frame
If the user selects a link corresponding to the following input 
 
     $href%http://www.w3.org/tr/rec-html32.html%HTML 3.2%1%$$
the results are displayed in the first frame of the current section. You can see the corresponding effect by selection the following link:
      HTML 3.2
If the frame number is not valid for the current section, the results are displayed in a separate window. For example, the following input 
 
     $href%http://www.w3.org/tr/rec-html32.html%HTML 3.2%0%$$
results in the following link
      HTML 3.2
Input File: omh/href.omh