CSS table tr hover one color/border and td hover another color/border without important

Question

I have the following fiddle.

Edit: with row boarder style be applied:

table,th,td
{
    border:2px solid black;
    border-collapse:collapse;
}
tr:hover td
{
    background-color:grey;
    border-top: 2px solid rgb(10, 0, 255);
    border-bottom: 2px solid rgb(10, 0, 255);
}
td:hover
{
    background-color:rgb(214,214,214) !important;
    border:2px solid red !important;
    border-top: 2px solid red;
    border-bottom: 2px solid red;
}

What I'm after is highlighting the ROW and CELL. Originally had thought doing sort of cross-hair, but column background coloring would need JavaScript, which I'll avoid for the time being.

On this would like the ROW:hover background color darkish and border emphasized.

The td:hover then to be a different color, and border emphasized differently.

Checked in Chrome, not checked Firefox.

Issues: need to use !important. Cell border-left and top not coloring to red?

So is there a way to write the CSS not using important!, and correct border styling on the TD cell?

Answer 1

You can do your original crosshairs idea with just CSS (no Javascript). Use the ::before and ::after pseudo-elements for highlighting. There's a slight issue with Firefox with this method, so I wrote a fix for it.

border-collapse: collapse makes borders on <tds> behave in strange ways. Instead, put your borders on the <trs> and <cols>. border-collapse: collapse also cuts off edges. To deal with that you have to get creative and draw an extra border on all the outside <tds> and <ths>. Even stranger, it "eats" a pixel on the top and two pixels on the bottom. So you need 3px on top to get a 2px border, and 4px on bottom to get a 2px border.

Demo:

CSS:

table {
    border-collapse: collapse;
    overflow: hidden;
    z-index: 1;
}
td, th, .row, .col, .ff-fix {
    cursor: pointer;
    padding: 10px;
    position: relative;
}
tr:last-child td {
    border-bottom: 4px solid black;
}
tr, col {
    border: 2px solid black;
}
th {
    border-top: 3px solid black;
}
th:last-child, td:nth-child(3n) {
    border-right: 4px solid black;
}
td:first-child, th:first-child {
    border-left: 3px solid black;
}
td:hover {
    border: 2px solid red;
}
td:hover:first-child {
    border-left: 3px solid red;
}
td:hover:nth-child(3n) {
    border-right: 4px solid red;
}
tr:last-child td:hover {
    border-bottom: 4px solid red;
}
td:hover::before,
.row:hover::before,
.ff-fix: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,
.ff-fix:hover::after { 
    background-color: #ffa;
    content: '\00a0';  
    height: 10000px;    
    left: 0;
    position: absolute;  
    top: -5000px;
    width: 100%;
    z-index: -1;        
}

HTML:

<table>
    <col /><col /><col />
    <tr>
        <th class="col">First Name</th>
        <th class="col">Middle Name</th>
        <th class="col">Last Name</th>
    </tr>
    <tr>
        <td>Peter</td>
        <td>Jeffery</td>
        <td>Griffin</td>
    </tr>
    <tr>
        <td>Lois</td>
        <td>Marie</td>
        <td>Griffin</td>
    </tr>
    <tr>
        <td>Margie</td>
        <td>Ann</td>
        <td>Thatcher</td>
    </tr>
</table>

Script:

function firefoxFix() {
    if ( /firefox/.test( window.navigator.userAgent.toLowerCase() ) ) {
        var tds = document.getElementsByTagName( 'td' ),
            ths = document.getElementsByTagName( 'th' );
        for( var index = 0; index < tds.length; index++ ) {
            tds[index].innerHTML = '<div class="ff-fix">' + tds[index].innerHTML + '</div>';                     
        };
        for( var index = 0; index < ths.length; index++ ) {
            ths[index].innerHTML = 
                  '<div class="' + ths[index].className + '">' 
                + ths[index].innerHTML 
                + '</div>';                     
            ths[index].className = '';
        };
        var style = '<style>'
            + 'td, th { padding: 0 !important; }' 
            + 'td:hover::before, td:hover::after { background-color: transparent !important; }'
            + '</style>';
        document.head.insertAdjacentHTML( 'beforeEnd', style );
    };
};

firefoxFix();