Question

How bad is to do a hide of a hidden element?

So, let’s say the element #myelement is hidden, and I do a $('#element').hide(). Is that bad? Should I check if it’s visible first?

Thanks!

Answer 1

jQuery checks if the element is visible and hides only if it’s visible: https://github.com/jquery/jquery/blob/master/src/css.js#L78

    } else if ( !values[ index ] && !isHidden( elem ) ) {
        jQuery._data( elem, "olddisplay", curCSS( elem, "display" ) );
    }

So you don’t need to perform additional checks. Any manual check would make the performance (and readability actually) worse.