html/css full background overlay div inside another div - css

Question

I have a simple < div > (without fixed hegiht) with a text in it:
<div id="section">
<div class="container">
<h1>text</h1>
<p>More text</p>
</div>
<!-- <div id="overlay"></div> -->
</div>
The CSS for this is something like:
#section {
background: red;
overflow: hidden;
}
It's possibile to add a div with a transparent image background?
The overlay sholud be hover the main red background, but under the text.
I think is something like this, but dont works:
#section #overlay {
position: relative;
top: 0px;
left: 0px;
width: 100%;
height: 100px; /* ??? */
background: green;
opacity: 0.1;
}

Answer 1

#section {
background: red;
display: block;
position: relative;
overflow: hidden;
}
#container {
position: relative;
width: 100%;
text-align: center;
z-index: 9999;
}
#overlay {
position: absolute;
left: 0;
width: 100%;
height: 100%;
top: 0;
background-color: rgba(0,0,0,0.3);
}

Answer 2

If I'm understanding you correctly, how about something like this:
HTML:
<div id="section">
<div id="container">
<h1>My background is transparent!</h1>
<p>More text</p>
</div>
</div>
CSS:
#section {
width: 300px;
background-color: red;
}
#container {
position: relative;
left: 50px;
width: 200px;
text-align: center;
background-color: rgba(0,0,0,0.3);
}
Results here: JSFiddle
If that's not what you wanted, can you be more specific about the positioning?

Answer 3

try below example using jquery ui will reduce the effort
<div id="dialog">Your non-modal dialog</div>
Open dialog
$('#open').click(function() {
$('#dialog').dialog('open');
});
jQuery(document).ready(function() {
jQuery("#dialog").dialog({
autoOpen: false,
modal: true,
open: function(){
jQuery('.ui-widget-overlay').bind('click',function(){
jQuery('#dialog').dialog('close');
})
}
});
});