How to hide the button if the content variable is filled?

There is a form:

<form action=v.php?ix=lbgDB52SK23&p0=$p0&iD=$id_pac method=post>
<table width=100%;height:34px;>
the <tr><td>Amount:<td><input name=z id=z style=width:100%;height:34px;font-size:1.3 em;padding-left:8px value='$Z'>
<tr height=5>
the <tr><td>Discount<td><input type=number min=0 max=100 value='$p[26]' name='s' size=3> %
the <tr><td valign=top><nobr>payment Type:
<td width=90%>
<input type=radio name=pay id=pay value=0 onclick=document.getElementById('qw').style.display=(this.checked)?'none':'none';>Cash<br>
<input type=radio name=pay id=pay value=3 onclick=document.getElementById('qw').style.display=(this.checked)?'none':'none';>Kartoshka<br></input>
<input type=radio name=pay id=pay onclick=document.getElementById('qw').style.display=(this.checked)?'block':'none';>Payment</input><textarea name=T id=qw style=display:none;border:1px;width:90%;height:80px;padding:8px; placeholder=Comment><".chr(47)."textarea>$p[27]
<tr height=7>
the <tr><td><td><input type=submit value=to Pay disabled=disabled style=border:0px;color:#fff;background:rgb(118,172,127);width:80px;height:25px;brder-radius:3px;> 
| $p[24] | $p[27]

Until the form has worked out the variable $p[24] empty
after the form has been update lbgDB5 set p24='paid'
Accordingly, as to make so that when field is not empty $p[24] submit to hide, or even hide the entire form and print information, for Example <div>$p[24]</div>
March 19th 20 at 09:06
1 answer
March 19th 20 at 09:08
if (isset($p[24])) ...

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