Submission not confirmed html php - php

Question

I have an form with submit button as follows in html :-
<div style="display: flex;">
<form name="myform"method="post" action="usdbtc.php" style="float:left;">
<div id="log_err"> <strong><?php if(isset($logerror)) { echo $logerror; } else { $dn = 'dn'; } ?></strong> </div>
<p><label style="float: left;">Price:</label><input class="input101" style="float: left;" type="text" name="username" id="box1" oninput="calculate()"><label style="float: right;">: BTC</label><input class="input101" style="float: right;" type="text" name="username" id="box2" oninput="calculate()">
<br><input class="input101" style="float: right;" type="text" name="username" id="result"><br><label style="padding: 10px;">Total BTC:</label>
<td rowspan="2">
<input type="hidden" id="myform" value="1"/>
<br><span class="orderbutton" type="submit" id="ordersell" onclick="myform.submit()">SELL</span></p>
</td>
</form>
<form name="yourform"method="post" action="usdbtc.php" style="float:right;">
<p><label style="float: left;">Price:</label><input class="input101" style="float: left;" type="text" name="username" id="box3" oninput="calculate()"><label style="float: right;">: BTC</label><input class="input101" style="float: right;" type="text" name="username" id="box4" oninput="calculate()">
<br><input class="input101" style="float: right;" type="text" name="username" id="resul"><br><label style="padding: 10px;">Total BTC:</label>
<td rowspan="2">
<input type="hidden" id="yourform" value="1"/>
<br>
<span class="orderbutton" type="submit" id="orderbuy" onclick="yourform.submit()">BUY</span></p>
</td>
</form>
</div>
And to check whether user clicked 'SELL' button i do in php :-
if($_POST['myform']){
echo 'yes';
}
else {
echo 'no';
}
I am always getting no after clicking button, is there anything wrong that I haved coded in the html or php part? Help is appreciated.. I just want to get the part for php
if($_POST['?']) {...
Remember there are two forms in the page with each having name and hidden input id.

Answer 1

<input type="hidden" id="myform" value="1"/>
Change id attribute to name
<input type="hidden" name="myform" value="1">
And there's a missing space in form tag