Salesforce Header and Sidebar is not displaying in visualforce Page

To resolve this issue, if you see inline=1 in the URL of the visualforce page, then that is the reason for the header and sidebar is not displayed.

To  resolve this issue, please use this below script in the visualforce page to display the sidebar and header.

<script>

if (location.href.match(/inline=1/)) window.top.location=location.href.replace(/inline=1/, '');

</script>