How to highlight a table's row and column when hovering over it?

I would like to do the exact same thing as done in this example: http://jsfiddle.net/ThinkingStiff/rUhCa/.

However, when I try to change the background color of the table, the hover and highlight stops working.

Below you can see my code:

HTML

<table>
    <tr>
        <th></th>
        <th class="col">50kg</th>
        <th class="col">55kg</th>
        <th class="col">60kg</th>
    </tr>
    <tr>
        <th class="row">160cm</th>
        <td>20</td>
        <td>21</td>
        <td>23</td>
    </tr>
</table>

CSS

table {
   border-spacing: 0;
   border-collapse: collapse;
   overflow: hidden;
   z-index: 1;
}

td, th, .row, .col {
   cursor: pointer;
   padding: 10px;
   position: relative;
}

td:hover::before,
.row:hover::before { 
   background-color: #ffa;
   content: '\00a0';  
   height: 100%;
   left: -5000px;
   position: absolute;  
   top: 0;
   width: 10000px;   
   z-index: -1;        
}

td:hover::after,
.col:hover::after { 
   background-color: #ffa;
   content: '\00a0';  
   height: 10000px;    
   left: 0;
   position: absolute;  
   top: -5000px;
   width: 100%;
   z-index: -1;        
}

Solution

Assuming this is something that you're looking for. You set z-index: -1 would hide the background highlighter when table has a background color as it has higher z-index value than negative values. But you really don't need them at all. You should use RGBA color - which specifies the opacity for a color to do the highlight works. Hope it helped!

table {
   border-spacing: 0;
   border-collapse: collapse;
   overflow: hidden;
   background-color: tomato;
}

td, th {
   padding: 10px;
   position: relative;
}

tr:hover{
   background-color: rgba(255, 255, 0, 0.5);
}

td:hover::after,th:hover::after { 
   background-color: rgba(255, 255, 0, 0.5);
   content: '\00a0';  
   height: 10000px;    
   left: 0;
   position: absolute;  
   top: -5000px;
   width: 100%;   
}

<table>
    <tr>
        <th></th>
        <th>50kg</th>
        <th>55kg</th>
        <th>60kg</th>
        <th>65kg</th>
        <th>70kg</th>
    </tr>

    <tr>
        <th class="row">160cm</th>
        <td>20</td>
        <td>21</td>
        <td>23</td>
        <td>25</td>
        <td>27</td>
    </tr>

    <tr>
        <th class="row">165cm</th>
        <td>18</td>
        <td>20</td>
        <td>22</td>
        <td>24</td>
        <td>26</td>
    </tr>

    <tr>
        <th class="row">170cm</th>
        <td>17</td>
        <td>19</td>
        <td>21</td>
        <td>23</td>
        <td>25</td>
    </tr>

    <tr>
        <th class="row">175cm</th>
        <td>16</td>
        <td>18</td>
        <td>20</td>
        <td>22</td>
        <td>24</td>
    </tr>

</table>

<script>

/* by: thinkingstiff.com
license: http://creativecommons.org/licenses/by-nc-sa/3.0/us/ */

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    );

document.body.insertAdjacentHTML( 
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document.head.insertAdjacentHTML( 'beforeEnd',
    '<style>'
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</script>