The gray filter display the element in the gray scale.
#example {
filter: gray();
}
The original
<img src="image/friend.gif" alt="IMG" width="170" height="140">

<div style="font: bold 170% sans-serif; color: red; width: 100%;">
Example text
</div>
The gray scale effect
<img src="image/friend.gif" alt="IMG" width="170" height="140" style="filter: gray();">

<div style="font: bold 170% sans-serif; color: red; width: 100%; filter: gray();"> Example text </div>