zIndex与position：relative：无效的chrome和safari

Question

在此示例中，表上有一个带有position：absolute的svg（位置：相对）。 我希望表格的第一行覆盖“ html”一词。 在firefox中，我可以通过使用z-index将第一行声明为position：relative ad来实现。 我不明白为什么这不适用于chrome和Safari。 我如何在Chrome和Safari中也能获得相同的结果？

在Safari和Chrome中：

在Firefox中：

 #codexpl th, #codexpl td{ padding:0.8em; border: 1px solid; } #codexpl th{ background-color:#6699FF; font-weight:bold; } #codexpl{ position: relative; } #svg{ position: absolute; top: 0; left: 0; width: 55%; z-index: 1; } tr:first-child{ position: relative; z-index: 2; } 

 <table id="codexpl"> <tr> <th>#</th> <th>Columna</th> <th>Relative</th> <th>Isso</th> </tr> <tr> <td>1</td> <td>This</td> <td>Column</td> <td>Is</td> </tr> <tr> <td>2</td> <td>Coloumn</td> <td>two</td> <td>this</td> </tr> <tr> <td>3</td> <td>is</td> <td>not equals</td> <td>a</td> </tr> <tr> <td>4</td> <td>the</td> <td>Column</td> <td>real</td> </tr> <tr> <td>5</td> <td>first</td> <td>One</td> <td>Coloumn</td> </tr> </table> <svg id="svg" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"> <title>HTML5 Logo</title> <polygon fill="#E44D26" points="107.644,470.877 74.633,100.62 437.367,100.62 404.321,470.819 255.778,512 "/> <polygon fill="#F16529" points="256,480.523 376.03,447.246 404.27,130.894 256,130.894 "/> <polygon fill="#EBEBEB" points="256,268.217 195.91,268.217 191.76,221.716 256,221.716 256,176.305 255.843,176.305 142.132,176.305 143.219,188.488 154.38,313.627 256,313.627"/> <polygon fill="#EBEBEB" points="256,386.153 255.801,386.206 205.227,372.55 201.994,336.333 177.419,336.333 156.409,336.333 162.771,407.634 255.791,433.457 256,433.399"/> <path d="M108.382,0h23.077v22.8h21.11V0h23.078v69.044H152.57v-23.12h-21.11v23.12h-23.077V0z"/> <path d="M205.994,22.896h-20.316V0h63.72v22.896h-20.325v46.148h-23.078V22.896z"/> <path d="M259.511,0h24.063l14.802,24.26L313.163,0h24.072v69.044h-22.982V34.822l-15.877,24.549h-0.397l-15.888-24.549v34.222h-22.58V0z"/> <path d="M348.72,0h23.084v46.222h32.453v22.822H348.72V0z"/> <polygon fill="#FFFFFF" points="255.843,268.217 255.843,313.627 311.761,313.627 306.49,372.521 255.843,386.191 255.843,433.435 348.937,407.634 349.62,399.962 360.291,280.411 361.399,268.217 349.162,268.217"/> <polygon fill="#FFFFFF" points="255.843,176.305 255.843,204.509 255.843,221.605 255.843,221.716 365.385,221.716 365.385,221.716 365.531,221.716 366.442,211.509 368.511,188.488 369.597,176.305"/> <svg> 

Answer 1

只是改变这个

tr:first-child{
  position: relative;
  z-index: 2;
}

对此

tr:first-child th{//be specific to th
  position: relative;
  z-index: 2;
}