Black transparent overlay on image - html

Question

I'm trying to get a light black overlay on the image when you hover on it (like the text) sorry I'm new to css and HTML!
help would be appreciated
HTML
<div id="con">
<div id="box1">
<p id="text1">
DESTINATIONS
</p>
</p>
<p id="text2">
AMALFI<BR>SORRENTO<BR>POSITANO</a>
</p>
<p id="text3">
THINGS TO DO
</p>
</p>
<p id="text4">
TOURS<BR>MUSUEMS<BR>SHOPPING</a>
</p>
</div>
css
#con {
width:1024px;
height:670px;
background-color: #161717;
}
#box1 {
float: left;
font-size: 25px;
width: 388px;
height: 477px;
background-image: url(media/trying1.png);
background-size: cover;
margin-left: 120px;
margin-top: 90px;
}
#text1 {
z-index:100;
color:white;
font-size:30px;
text-align: center;
margin-top:80px;
line-height:55px;
opacity: 0;
transition: all 0.5s;
}
#box1:hover #text1 {
opacity: 1;
}

Answer 1

This can be done with :before or :after
#box1{
position:relative;
}
#box1:before{
content:'';
position:absolute;
top:0;
left:0;
right:0;
bottom:0;
background:black;
opacity:0;
z-index:0;
}
#box1:hover:before{
opacity:.6;
transition: all 0.5s;
}
#box1 > *{
position:relative;
z-index:1;
}
http://jsfiddle.net/4bo4zju7/3/

Answer 2

CS3 is great! You no longer need JS for simple rollover effects. Gopalraju's above code should work and so does my example below. You can have a fiddle with it and use the code as you see fit.
The parent div, has a black page background, and the imgdiv changes everything inside it to a opacity by 50% on the mouse rolling over the div. In this case the image is inside the div.
There are a few ways of doing this. This is just another one to ad into the mix. Good luck.
.parentdiv {
background-color:#000;
height:100%;
width:100%;
}
.imgdiv {
padding:30px;
}
.imgdiv a{
opacity: 1;
filter: alpha(opacity=100);
-webkit-transition: opacity 0.5s linear;
}
.imgdiv a:hover {
opacity: 0.5;
filter: alpha(opacity=50);
-webkit-transition: opacity 0.5s linear;
}
<div class="parentdiv">
<div class="imgdiv">
<a href="http://www.domain.com.au/link.html">
<img src="http://placehold.it/350x150" alt="image" height="150" width="350">
</a>
</div>
</div>