title: How to check if a textbox is empty and return an error using PSP
body: <p>I am using PL/SQL Server Pages to retrieve data from database. I have 2 files, first.psp and second.psp</p>
  
  <p>In first.psp, I wrote the code for a textbox using input tag and the name of this textbox is 'age'. In second.psp, I declared age as parameter using</p>
  
  <p>--> &lt;%@ plsql parameter = "age" type = "VARCHAR2"%></p>
  
  <p>In the form tag of first.psp, I used method = "post" and action = "second.psp"</p>
  
  <p>Now I want to check if the textbox value is a number, otherwise return error. It should also return error if the textbox is empty.
  If I say,</p>
  
  <p>IF age = ' ' THEN</p>
  
  <p>/<em>print error</em>/</p>
  
  <p>ELSE</p>
  
  <p>/<em>blah blah blah</em>/</p>
  
  <p>END IF;</p>
  
  <p>and while running the first.psp in the browser, I fill nothing in the textbox, even then the control goes to ELSE part but it actually should go to the IF part. Can anyone please tell me where I am going wrong?</p>
  
  <p>Thanks.</p>