title: MAKE drop down ready only if value is selected
body: <p>i am new in programming </p>
  
  <p>i have 6 drop down in one page 1 want them to make them read only (non editable) 
  if value is selected
  and rest of the drop down should not be read only if value is selected</p>
  
  <p>is there any way i can check all the Drop down in one condition/check(at one go)</p>
  
  <p>thanks in advance</p>