<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<body onload="sirchange()">
<p id="demo" onclick="myFunction()" >data</p>
<select id="sir" onchange="sirchange()">
<option>Mufgr </option>
<option>Mjhjs </option>
</select>
<select id="name" onchange="namechange()">
<option>jon </option>
<option>dany </option>
</select>
function sirchange() {
var name=document.getElementById("name").value;
var sirname=document.getElementById("sir").value;
document.getElementById("demo").innerHTML = sirname+""+name;
}
function namechange() {
var name=document.getElementById("name").value;
var sirname=document.getElementById("sir").value;
document.getElementById("demo").innerHTML = sirname+""+name;
}