Why does my text div spill out past my container div? - html

Question

I really need your help,
I can't seem to figure out as to why my div #text spills out past my container div? It should fit nicely inside its container?
Here is the CSS markup:
height: 100px;
width: 500px;
bottom: 50%;
right: 50%;
position: absolute;
display: none;
}
#container {
background: #FFF;
left: 50%;
padding: 10px;
top: 50%;
margin: 0;
padding: 0;
height: 100%;
border: 2px solid rgb(100,139,170);
height: 100%;
position: relative;
}
.topbar {
cursor: pointer;
color: white;
background: rgb(100,139,170);
padding: 4px;
font-weight: bold;
}
#text {
height: 100%;
border: 1px solid red;
}
HTML:
<div id="wrapper">
<div id="container">
<div style="float:left;" class="topbar">Custom Dialog Box</div><div class="topbar" style="text-align: right;">Close</div>
<div id="text"><p>test</p></div>
</div>
</div>
Here is a snapshot of the problem:

Answer 1

The height of #text is 100% which means it gets the height of the containing block, in this case #container. Both the height of #text as well as the #container are 500px. But #text is being pushed down by it's sibling .topbar, causing it to overflow.
To solve this you can use the css property overflow:auto as suggested by Jarred Farrish in the comments

Answer 2

Because #test {height:100%;} it will look for it's parent's height, all the way to #wrapper which is set to height:100px, so #test will get the same height, plus the borders, and the #container doesn't have enough space to hold it (due to the extra blue bar), so it overflows.
I also noticed the layout can be done simpler as follows.
#wrapper {
height: 100px;
width: 500px;
bottom: 50%;
right: 50%;
margin-bottom: -50px; /*half height*/
margin-right: -250px; /*half width*/
position: absolute;
/* display: none; */
}
#container {
background: #FFF;
border: 2px solid rgb(100, 139, 170);
}
.topbar {
cursor: pointer;
color: white;
background: rgb(100, 139, 170);
padding: 4px;
font-weight: bold;
}
#text {
border: 1px solid red;
}
<div id="wrapper">
<div id="container">
<div style="float:left;" class="topbar">Custom Dialog Box</div>
<div class="topbar" style="text-align: right;">Close</div>
<div id="text">
<p>test</p>
</div>
</div>
</div>

Answer 3

You are taking the height of the #container but remember that there is also sort of a header at the top of the container so the text height should be < 100% because you have to substract the height of the dialog header.

Answer 4

Amir got point, the way you can "fix" this is to add padding to content, so you got safe space.
CodePen Sample
<div id="wrapper">
<div id="container">
<div style="float:left;" class="topbar">Custom Dialog Box</div><div class="topbar" style="text-align: right;">Close</div>
<div id="text"><p>test</p></div>
</div>
#wrapper{
height: 100px;
width: 500px;
bottom: 50%;
right: 50%;
margin-right: -250px;
position: absolute;
border: 1px solid yellow;
}
#container {
background: #FFF;
left: 0%;
padding-bottom: 30px;
top: 0%;
margin: 0;
height: 100%;
border: 2px solid rgb(100,139,170);
position: relative;
}
.topbar {
cursor: pointer;
color: white;
background: rgb(100,139,170);
padding: 4px;
font-weight: bold;
border: 1px solid green;
}
#text {
height: 100%;
border: 1px solid red;
}
I also fixed positioning for you.