I want know about <? =@variablename ?> in php

[bhoomanandam]

sir,
am beginer to php mysql am facing problems as following code..
i seen this code on web but am confusing about the php block of code as follows. why we need this php code here while storing in to database, only one thing i.e <? =@s1 ?>
where $s1,$s2,$s3 are the inserting values for empno ,ename,esal(pos t $s1,$s2,$s3).
1.<input type='text' name='empno' size='30' autofocus required value='<?php if(isset($s1)) echo $s1 ?>'>
2.<input type='text' name='ename' size='30' required value='<? =@$s2 ?>' >
3.<input type='text' name='sal' size='10' required value='<? =@$s3 ?>'

[Dormilich]

don't do that. error supression like that is a sign of bad design. you should never ever use non-existent variables in the output.