CSS transition between left -> right and top -> bottom positions

Is it possible to use CSS transitions to animate something between a position set as left: 0px to right: 0px so it goes all the way across the screen? I need to accomplish the same thing with top to bottom. Am I stuck calculating the screen width / object-size?

#nav {
    position: absolute;
    top: 0px;
    left: 0px;
    width: 50px;
    height: 50px;
    -webkit-transition: all 0.5s ease-out;
}

.moveto {
    top: 0px;
    right: 0px;
}

and then I use jQuery's .addClass

You can animate the position (top, bottom, left, right) and then subtract the element's width or height through a CSS transformation.

Consider:

$('.animate').on('click', function(){
  $(this).toggleClass("move");
})

     .animate {
        height: 100px;
        width: 100px;
        background-color: #c00;
        transition: all 1s ease;
        position: absolute;
        cursor: pointer;
        font: 13px/100px sans-serif;
        color: white;
        text-align: center;
      }

                               /* ↓ just to position things  */
      .animate.left   { left: 0;   top: 50%;  margin-top: -100px;}
      .animate.right  { right: 0;  top: 50%;  }
      .animate.top    { top: 0;    left: 50%; }
      .animate.bottom { bottom: 0; left: 50%; margin-left: -100px;}


      .animate.left.move {
        left: 100%; 
        transform: translate(-100%, 0);
      }

      .animate.right.move {
        right: 100%; 
        transform: translate(100%, 0);
      }

      .animate.top.move {
        top: 100%; 
        transform: translate(0, -100%);
      }

      .animate.bottom.move {
        bottom: 100%; 
        transform: translate(0, 100%);
      }

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
Click to animate
<div class="animate left">left</div>
<div class="animate top">top</div>
<div class="animate bottom">bottom</div>
<div class="animate right">right</div>

And then animate depending on the position...

This worked for me on Chromium. The % for translate is in reference to the size of the bounding box of the element it is applied to so it perfectly gets the element to the lower right edge while not having to switch which property is used to specify it's location.

topleft {
  top: 0%;
  left: 0%;
}
bottomright {
  top: 100%;
  left: 100%;
  -webkit-transform: translate(-100%,-100%);
}

For elements with dynamic width it's possible to use transform: translateX(-100%); to counter the horizontal percentage value. This leads to two possible solutions:

1. Option: moving the element in the entire viewport:

Transition from:

transform: translateX(0);

to

transform: translateX(calc(100vw - 100%));

#viewportPendulum {
  position: fixed;
  left: 0;
  top: 0;
  animation: 2s ease-in-out infinite alternate swingViewport;
  /* just for styling purposes */
  background: #c70039;
  padding: 1rem;
  color: #fff;
  font-family: sans-serif;
}

@keyframes swingViewport {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(calc(100vw - 100%));
  }
}

<div id="viewportPendulum">Viewport</div>

2. Option: moving the element in the parent container:

Transition from:

transform: translateX(0);
left: 0;

to

left: 100%;
transform: translateX(-100%);

#parentPendulum {
  position: relative;
  display: inline-block;
  animation: 2s ease-in-out infinite alternate swingParent;
  /* just for styling purposes */
  background: #c70039;
  padding: 1rem;
  color: #fff;
  font-family: sans-serif;
}

@keyframes swingParent {
  from {
    transform: translateX(0);
    left: 0;
  }
  to {
    left: 100%;
    transform: translateX(-100%);
  }
}

.wrapper {
  padding: 2rem 0;
  margin: 2rem 15%;
  background: #eee;
}

<div class="wrapper">
  <div id="parentPendulum">Parent</div>
</div>

---

Demo on Codepen

Note: This approach can easily be extended to work for vertical positioning. Visit example here.

In more modern browsers (including IE 10+) you can now use calc():

.moveto {
  top: 0px;
  left: calc(100% - 50px);
}