 <p>See the first input field for full width:</p> <p><div class="snippet" data-lang="js" data-hide="false"> <div class="snippet-code"> <pre class="snippet-code-html lang-html prettyprint-override"><code> &lt;form method="post" class="mobile-login-form _5spm" id="u_0_0" novalidate="1" data-autoid="autoid_1"&gt;&lt;input name="lsd" value="AVpe_Wp1" autocomplete="off" type="hidden"&gt;&lt;input name="charset_test" value="€,´,€,´,水,Д,Є" type="hidden"&gt;&lt;input name="version" value="1" type="hidden"&gt;&lt;input id="ajax" name="ajax" value="0" type="hidden"&gt;&lt;input id="width" name="width" value="0" type="hidden"&gt;&lt;input id="pxr" name="pxr" value="0" type="hidden"&gt;&lt;input id="gps" name="gps" value="0" type="hidden"&gt;&lt;input id="dimensions" name="dimensions" value="0" type="hidden"&gt;&lt;input name="m_ts" value="1421117640" type="hidden"&gt;&lt;input name="li" value="yIi0VOqdqMbfGzXVr-lypMC-" type="hidden"&gt;&lt;div class="_56be _5sob"&gt;&lt;div class="_55wo _55x2 _56bf"&gt;&lt;input style="width: 100%;" autocorrect="off" autocapitalize="off" class="_56bg _55ws _5ruq" name="email" placeholder="Email Address" type="email"&gt;&lt;p&gt;&lt;input autocorrect="off" autocapitalize="off" class="_56bg _55ws _5ruq" placeholder="Password" name="pass" id="password" type="password"&gt;&lt;/p&gt;&lt;div class="_55ws"&gt;&lt;button type="submit" value="Submit" class="_56bs _56b_ _56bw _56bu" name="login" id="u_0_1" data-sigil="touchable"&gt;&lt;span class="_55sr"&gt;Submit&lt;/span&gt;&lt;/button&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;noscript&gt;&amp;lt;input type="hidden" name="_fb_noscript" value="true" /&amp;gt;&lt;/noscript&gt;&lt;/form&gt;</code></pre> </div> </div> </p> <p>It's this line:</p> <pre><code>&lt;input style="width: 100%;" autocorrect="off" autocapitalize="off" class="_56bg _55ws _5ruq" name="email" placeholder="Email Address" type="email"&gt; </code></pre>