I am creating a poll in php. I have a table with an id column.

When a user submits a choice, I want the php to first query the database and check whether the table "id" has the id of the current user. 

I am pretty new at mysql, can someone help me with the query?
['https://Stackoverflow.com/questions/1992827', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/107922/']
Give the element an `id` attribute. You can then use Javascript to check it's innerHTML property once the page has loaded. If innerHTML has a length of zero, then you can set it's display property to none. [This page](http://www.tizag.com/javascriptT/javascript-innerHTML.php) might help if you don't know your javascript.

This is still a mucky way to play. If you know the element shouldn't be rendered before you serve the page it would be better to omit it altogether. If you don't want to omit the element, just hide it, then force it into hiding; `style="display: none"`
Don't use padding on container, use margin on content. Than when there is no content, container remains invisible.