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FETCHING A LIST OF KEYWORDS FROM THE QUERY:

@keywords = $query->keywords

If the script was invoked as the result of an <ISINDEX> search, the parsed keywords can be obtained as an array using the keywords() method.
FETCHING THE NAMES OF ALL THE PARAMETERS PASSED TO YOUR SCRIPT:

@names = $query->param

If the script was invoked with a parameter list (e.g. "name1=value1&name2=value2&name3=value3"), the param() method will return the parameter names as a list. If the script was invoked as an <ISINDEX> script and contains a string without ampersands (e.g. "value1+value2+value3") , there will be a single parameter named "keywords" containing the "+"-delimited keywords.

NOTE: As of version 1.5, the array of parameter names returned will be in the same order as they were submitted by the browser. Usually this order is the same as the order in which the parameters are defined in the form (however, this isn't part of the spec, and so isn't guaranteed).