JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>


<form action="" method="post">
<select name="tm_1_id" id="tm_1_id">
<option>Sajjad</option>
<option>Mahmood</option>
<option>Ahsan</option>
<option>Usman</option>

</select>
<br>
<select name="tm_2_id" id="tm_2_id">
<option>Sajjad</option>
<option>Mahmood2</option>
<option>Ahsan2</option>
<option>Usman2</option>

</select>
<br>
<input type="submit" name="submit" id="submit" value="Create" onClick="return checkDouble();" />
</form>

JavaScript

var mmbr1 = document.getElementById("tm_1_id");
		var tm1 = mmbr1.options[mmbr1.selectedIndex].value;
		var mmbr2 = document.getElementById("tm_2_id");
		var tm2 = mmbr2.options[mmbr2.selectedIndex].value;
		function checkDouble(){
		if (2>1)
			{
			alert (tm2);
return false;
		}