Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="element el1"></div>
<div class="element el2"></div>

SassMeister-input.scss

// ----
// Sass (v3.3.8)
// Compass (v1.0.0.alpha.19)
// ----

// From: http://thesassway.com/intermediate/leveraging-sass-mixins-for-cleaner-code
// With keyword arguments, there's no need to preserve the order of the arguments

@mixin border-radius($radius: 5px, $moz: true, $webkit: true, $ms: true) {
  @if $moz    { -moz-border-radius:    $radius; }
  @if $webkit { -webkit-border-radius: $radius; }
  @if $ms     { -ms-border-radius:     $radius; }
  border-radius: $radius;
}

.element {
  display: block;
  max-width: 200px;
  height: 50px;
  background: hotpink;
  margin: 5px;
}

.el1 {
  @include border-radius(30% 10px, true, true, true);
}

.el2 {
  @include border-radius($ms: false, $radius: 10px);
}

SassMeister-output.css

.element {
  display: block;
  max-width: 200px;
  height: 50px;
  background: hotpink;
  margin: 5px;
}

.el1 {
  -moz-border-radius: 30% 10px;
  -webkit-border-radius: 30% 10px;
  -ms-border-radius: 30% 10px;
  border-radius: 30% 10px;
}

.el2 {
  -moz-border-radius: 10px;
  -webkit-border-radius: 10px;
  border-radius: 10px;
}

SassMeister-rendered.html

<div class="element el1"></div>
<div class="element el2"></div>