html - div的垂直和水平中心

Question

谁能告诉我为什么这段代码不起作用

 <div id="dojam_text_container" style="width: 300px; height: 300px; 
                      margin:auto;  background-color:Blue;">
                      <div style="display:table-cell; vertical-align:middle;">
                    <span id="text_dojmovi1" style="">"bla bla bla</span></div>
</div>

这确实..

 <div style="position:absolute; top:10vw; left:10vh;">
    <div style=" border: dotted red 1px; background-color:white; width:20vw; height:
           20vh; display:table-cell; text-align:center; vertical-align:middle; position:relative;">
           <span> I am some centered shrink-to-fit content! 
               <br />
           </span>
     </div>
 </div>

Answer 1

将 display:table 给你的父 div

<div style="position: absolute;display:table;width:300px; height:300px; top:100px; left:100px; background-color:Black;">
 .............
</div>

Fiddle

Docs to understand tabular structure using divs