javascript multiple input textarea validation
<p><br />
I have 'n' numbers in a TEXTAREA on a form. After the user enters some value in the TEXTAREA, I need to validate it's not a duplicate of any other value.</p>

<p>Ex : </p>

<p>TEXTAREA_1 value =<br>
10<br>
20<br>
30<br>
40<br>
10</p>

<p>It should alert and say 'value 10 was entered more than once'. Please help me with the Javascript.</p>

<p>Thank you so much.</p>
