Which am I better off doing? .hide() is quicker than writing out .css(\"display\", \"none\"), but what’s the difference and what are both of them a
To use both is a nice answer; it's not a question of either or.
The advantage of using both is that the CSS will hide the element immediately when the page loads. The jQuery .hide will flash the element for a quarter of a second then hide it.
In the case when we want to have the element not shown when the page loads we can use CSS and set display:none & use the jQuery .hide(). If we plan to toggle the element we can use jQuery toggle.