Question

It gets really annoying, especially when using these techniques as much as I am, to not only add these, but then to change them even the slightest, because I have to do it three times, rather than just once.

Example:

-webkit-border-radius: 5px;
-moz-border-radius: 5px;
 border-radius:5px;

There must be some way to only have to do this once, a plugin or something.

Answer 1

Use a CSS preprocesser like SASS. The mixin capability allows something like this:

@mixin border-radius($radius) {
    -webkit-border-radius: $radius;
    -moz-border-radius: $radius;
     border-radius: $radius;
}

Then you can just reference the mixin like this:

@include border-radius(5px);