PHP速记变量切换表行背景色

Question

I've been using the following shorthand in php lately for defining table row background colors.

Are there are caveats to using this method , other than perhaps obscurity?

 <?php $style = 'style="background-color:#CCC;"'; ?>
 <tr <?php if ($i = !$i) echo $style; ?>>
      <td><input /></td>
 <tr>

What's happening is $i = !$i means $i cannot equal $i, so if $i is true the first time, it becomes false, and vice versa. The if of course checks the value true or false each time, thereby outputting the style every other time and obtaining the every-other background effect.

Answer 1

I did not get your logic of $i != $i, but still if i understood that you want different colors for alternating TR , it can be done at css level. Use CSS - nth Property.

try :

tr:nth-child(odd) {
    background: red;
}

tr:nth-child(even) {
    background: blue;
}

OR

tr:nth-child(2n+1) {
     background: yellow;
} 

Note: Use 2n+0 or 2n+1 for alternate - starting first row + 2, or 2nd row + 2