Placeholder Mixin SCSS/CSS

Question

I'm trying to create a mixin for placeholders in sass.

This is the mixin I've created.

@mixin placeholder ($css) {
  ::-webkit-input-placeholder {$css}
  :-moz-placeholder           {$css}
  ::-moz-placeholder          {$css}
  :-ms-input-placeholder      {$css}  
}

This is how I'd like to include the mixin:

@include placeholder(font-style:italic; color: white; font-weight:100;);

Obviously this isn't going to work because of all the colons and semi-colons that's being passed through to the mixin, but... I'd really like to just input static css and pass it through exactly like the above function.

Is this possible?

Answer 1

You're looking for the @content directive:

@mixin placeholder {
  ::-webkit-input-placeholder {@content}
  :-moz-placeholder           {@content}
  ::-moz-placeholder          {@content}
  :-ms-input-placeholder      {@content}  
}

@include placeholder {
    font-style:italic;
    color: white;
    font-weight:100;
}

SASS Reference has more information, which can be found here: http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#mixin-content

---

As of Sass 3.4, this mixin can be written like so to work both nested and unnested:

@mixin optional-at-root($sel) {
  @at-root #{if(not &, $sel, selector-append(&, $sel))} {
    @content;
  }
}

@mixin placeholder {
  @include optional-at-root('::-webkit-input-placeholder') {
    @content;
  }

  @include optional-at-root(':-moz-placeholder') {
    @content;
  }

  @include optional-at-root('::-moz-placeholder') {
    @content;
  }

  @include optional-at-root(':-ms-input-placeholder') {
    @content;
  }
}

Usage:

.foo {
  @include placeholder {
    color: green;
  }
}

@include placeholder {
  color: red;
}

Output:

.foo::-webkit-input-placeholder {
  color: green;
}
.foo:-moz-placeholder {
  color: green;
}
.foo::-moz-placeholder {
  color: green;
}
.foo:-ms-input-placeholder {
  color: green;
}

::-webkit-input-placeholder {
  color: red;
}
:-moz-placeholder {
  color: red;
}
::-moz-placeholder {
  color: red;
}
:-ms-input-placeholder {
  color: red;
}