HELP PLS!!

[Anonymous]

I'm very noobish to PHP..........

here is my problem: What is the PHP equivalent of the following asp code?
I mean, i wanna pull out the query string of the previous page that leads to this and use it in an IF statemen like this one but in php form.

ASP CODE:

<%if Request("viewby")= "author" then%>
<FORM NAME="SelectbyAuthor" ACTION="SearchResults.asp?Displayby=author" Method="Post">
Enter Author:<INPUT TYPE="text" Name="txtAuthor" Value="">
<INPUT TYPE="submit" Name="cmdSearch" Value="Search">

</FORM>

<%end if%>

 

[Anonymous]

This is php-code:

<?
 if ($viewby=="author") 
 {
  echo "<FORM NAME='SelectbyAuthor' ACTION='SearchResults.php?  Displayby=author' Method='Post'> 
Enter Author:<INPUT TYPE='text' Name='txtAuthor' Value=''> 
<INPUT TYPE='submit' Name='cmdSearch' Value='Search'> 
</FORM>"
}