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home / docs / archive / version 4 / instructions / step 1
V4 Setup Instructions
Step 1 of 6
The following script must be placed early in your document. It is available to all
JavaScript-enabled browsers:
<HTML>
<HEAD>
<SCRIPT LANGUAGE="JavaScript" TYPE="text/javascript">
<!--
if(window.event + "" == "undefined") event = null;
function HM_f_PopUp(){return false};
function HM_f_PopDown(){return false};
popUp = HM_f_PopUp;
popDown = HM_f_PopDown;
//-->
</SCRIPT>
Four dummy functions are declared, HM_f_PopUp(),
HM_f_PopDown(), popUp() and
popDown(). These functions may be called by links in the document,
links that are visible to all browsers. The actual functions are re-declared in the menu script later, for
menu-enabled browsers. By placing these "dummy" functions here, older browsers will not generate an
error when they encounter a menu-enabled link since they will find and execute these dummy versions.
HM_f_PopUp() and HM_f_PopDown() are
the actual functions declared in HierMenus; the other two functions are provided for compatibility
with previous versions of HM that used popUp() and
popDown().
Fourth generation browsers have a built-in event object,
passed as an argument to HM_f_PopUp(). Old browsers do not have this
object, so they consider event to be a user-defined variable. We
must, therefore, define it as a dummy variable for these browsers to again avoid errors.
Note: If you are writing for a version 4+ environment only, and you are only
using permanently available menus (i.e., you are not using onMouseOver
and onMouseOut within existing page links to display your menus -
more on this later), you may omit this step.
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