Why overflow-y is not working? - html

Question

In the code below, why 'overflow-y' is not working in class 'dialogo'?
I tried somehow and I could not.
Responsive CSS seems confusing many times.
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
html,body,div,menu,
video {
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
overflow-x: hidden;
}
</style>
<style>
html {
background: #E2CE99;
}
.container {
position: relative;
width: 70%;
background-color: red;
font-family: helvetica, sans-serif;
border: 2px solid black;
float: left;
left: 2%;
padding-left: 2px;
}
.containerd {
position: relative;
width: 70%;
background-color: white;
font-family: helvetica, sans-serif;
border: 2px solid black;
float: right;
right: 2%;
padding-left: 2px;
}
.content {
position: relative;
padding-top: 10px;
}
.content p {
}
#header {
z-index: 2;
position: fixed;
width: 100%;
height: 60px;
line-height: 60px;
background: #CC1111;
color: white;
}
#header h1 {
position: absolute;
top: 0;
left: 0;
text-transform: uppercase;
}
.dialogo{
resize: vertical;
width: 100%;
top: 1%;
position: relative;
font-size: 15px;
overflow-y: scroll;
background-color: white;
word-wrap:break-word;
text-align: left;
border:1px solid black;
height: 50%;
}
</style>
</head>
<header id="header">
<center>Jhon</center>
</header>
<div style="padding-top: 70px;"></div>
<div class = dialogo disabled id="texConv" name="texConv">
<div class="content">
<div class="container">
<p>HELLO</p>
</div>
</div>
<div class="content">
<div class="containerd">
<p>HELLO</p>
</div>
</div>
</div>
<br>
<div class="content">&nbsp 2017</div>
</html>
So I would like to know how to put a height in percentages for a div containing as boxes and turn on the scroll-Y.

Answer 1

For overflow-y to work, the height of the content in the element needs to exceed the specified height. I changed the height to 5em and you can see it's working.
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
html,
body,
div,
menu,
video {
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
overflow-x: hidden;
}
</style>
<style>
html {
background: #E2CE99;
}
.container {
position: relative;
width: 70%;
background-color: red;
font-family: helvetica, sans-serif;
border: 2px solid black;
float: left;
left: 2%;
padding-left: 2px;
}
.containerd {
position: relative;
width: 70%;
background-color: white;
font-family: helvetica, sans-serif;
border: 2px solid black;
float: right;
right: 2%;
padding-left: 2px;
}
.content {
position: relative;
padding-top: 10px;
}
.content p {}
#header {
z-index: 2;
position: fixed;
width: 100%;
height: 60px;
line-height: 60px;
background: #CC1111;
color: white;
}
#header h1 {
position: absolute;
top: 0;
left: 0;
text-transform: uppercase;
}
.dialogo {
resize: vertical;
width: 100%;
top: 1%;
position: relative;
font-size: 15px;
overflow-y: scroll;
background-color: white;
word-wrap: break-word;
text-align: left;
border: 1px solid black;
height: 5em;
}
</style>
</head>
<header id="header">
<center>Jhon</center>
</header>
<div style="padding-top: 70px;"></div>
<div class="dialogo" disabled id="texConv" name="texConv">
<div class="content">
<div class="container">
<p>HELLO</p>
</div>
</div>
<div class="content">
<div class="containerd">
<p>HELLO</p>
</div>
</div>
</div>
<br>
<div class="content">&nbsp 2017</div>
</html>