Coloring the table with alternate color - php

Question

Below i have added my css file and my html file i need to color my table with alter name color but its not working i don't know where i have done the mistake.
CSS FILE :-
table.gridtable{
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
float:center;
border-width:1px;
border-style:groove;
border-color:black;
border-collapse:collapse;
width:600px;
}
table.gridtable th{
border-width:1px;
padding:3px;
border-style:solid;
border-color:black;
}
table.gridtable td{
border-width:1px;
padding:3px;
border-style:solid;
border-color:black;
}
.oddrowcolor{
background-color: black;
}
.evenrowcolor{
background-color: red;
}
table.gridtable td.darkcol{
border-top:0px;
border-bottom:0px;
border-right: 1px;
}
table.gridtable td.emptycol{
border-bottom:0px;
border-right: 1px;
}
HTML & PHP:-
<table class="gridtable" id="alternatecolor" align="center"
<tr><th>disease Name/th><th>Gene Name/th><th>OMIM Number</th></tr>
<?php
$dbhandle = mysql_connect($hostname, $username, $password) or die("Unable to connect to MySQL");
$selected = mysql_select_db("missensencemuttation",$dbhandle) or die("Could not select disease");
$result = mysql_query("SELECT DISTINCT * FROM `gene_data` ORDER BY disease_name");
$last=" ";
while($row = mysql_fetch_array($result))
$now=$row[2];
if($last != $now){
$rcnt=mysql_query("select count(gene_name) from gene_data where gene_name='$now'");
if($rcnt==1){
echo "<tr><td>";
echo "<a href='d1.php?d_name=".$row['disease_name']."'>".$row['disease_name'];
echo "</a></td>";
echo "<td>".$row['gene_name']."</td>";
echo "<td>".$row['ommi_number']."</td></tr>";
}
else{
echo "<tr><td class='emptycol'>";
echo "<a href='d1.php?d_name=".$row['disease_name']."'>".$row['disease_name'];
echo "</a></td>";
echo "<td>".$row['gene_name']."</td>";
echo "<td>".$row['ommi_number']."</td></tr>";
}
}
else
{
echo "<tr'>";
echo "<td class='darkcol'>";
echo '&nbsp';
echo "</td>";
echo "<td>".$row['gene_name']."</td>";
echo "<td>".$row['ommi_number']."</td></tr>";
}
$last=$row[2];
can any one help me with this ??

Answer 1

Maybe I'm misunderstanding, but it looks like you want to apply oddrowcolor or evenrowcolor to alternating rows - but in your actual php/html, I don't see those class names anywhere. They're not being put on the rows, so their rules wont be applied. Just add them to the appropriate <tr> tags in your php and it should work.
Alternatively you could use the nth-of-type selector to apply the rules without altering your php:
tr:nth-of-type(odd) {
background-color: black;
}
tr:nth-of-type(even) {
background-color: red;
}

Answer 2

If you want alternate colors for each table row, then a simple CSS should do it. This way, if you want to insert new rows dynamically, it will adjust the colors automatically.
.stripped-rows:nth-child(odd){
background-color:red;
}
.stripped-rows:nth-child(even){
background-color:blue;
}
and html ...
<table>
<tr class = 'stripped-rows'>
<td>sad</td>
</tr>
<tr class = 'stripped-rows'>
<td>sad</td>
</tr>
<tr class = 'stripped-rows'>
<td>sad</td>
</tr>
DEMO