CSS triangle :before element

问题

I'm using bootstrap, trying to make a div have a CSS triangle before it.

http://jsfiddle.net/B2XvZ/11/

Here is my non-working code:

.d:before {
  width: 0px;
  height: 0px;
  border-style: solid;
  border-width: 10px 15px 10px 0;
  border-color: transparent #dd4397 transparent transparent;  
}

The way I'd like it to look is for there to be a pink left-pointing triangle right before the text "this", with no gap between it and the div. I've tried to do this by floating the elements also, with no success.

回答1:

You need to specify the content property.

For positioning, add position:relative to the parent, and then absolutely position the arrow -15px to the left.

jsFiddle example

.d {
    position:relative;
}

.d:before {
    content:"\A";
    border-style: solid;
    border-width: 10px 15px 10px 0;
    border-color: transparent #dd4397 transparent transparent;
    position: absolute;
    left: -15px;
}

回答2:

You need content property and some other

.d:before {
  content: '';
  width: 0px;
  height: 0px;
  border-style: solid;
  border-width: 10px 15px 10px 0;
  border-color: transparent #dd4397 transparent transparent;  
  display: inline-block;
  vertical-align: middle;
  margin-right: 5px;
}

来源：https://stackoverflow.com/questions/20589780/css-triangle-before-element