兩端對齊

    <div class="justifySpan">
        <span>齐</span>
        <span>齐</span>
    </div>

.justify {
        display: -webkit-box;
          display: -ms-flexbox;
          display: -webkit-flex;
          display: flex;
          -webkit-box-pack: justify;
          -ms-flex-pack: justify;
          -webkit-justify-content: space-between;
          justify-content: space-between;
    }

    <div class="justifySpan">
        <span>齐</span>
        <span>齐</span>
    </div>

    .justifySpan {
    text-align:justify;
    text-justify:distribute-all-lines;/*ie6-8*/
    text-align-last:justify;/* ie9*/
    -moz-text-align-last:justify;/*ff*/
    -webkit-text-align-last:justify;/*chrome 20+*/
    }
    .justifySpan:after{
      content:"";
      display: inline-block;
      width:100%;
      overflow:hidden;
      height:0;
    }

    <div class="justifySpan">
        <div>左边对齐</div>
        <div>右边对齐</div>
    </div>

.justifySpan {
    text-align:justify;
    text-justify:distribute-all-lines;/*ie6-8*/
    text-align-last:justify;/* ie9*/
    -moz-text-align-last:justify;/*ff*/
    -webkit-text-align-last:justify;/*chrome 20+*/
    }
    .justifySpan:after{
      content:"";
      display: inline-block;
      width:100%;
      overflow:hidden;
      height:0;
    }
    .justifySpan div{
        display: inline-block;
    }