Một ví dụ nho nhỏ
<!
DOCTYPE
html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<
head
>
<
meta
http-equiv
=
"Content-Type"
content
=
"text/html; charset=iso-8859-1"
/>
<
title
>Java script</
title
>
<
style
>
input[type=text]
{
width:50px;
text-align:center;
border:thin solid gray;
padding: 2px 5px 2px 5px;
border-radius: 3px 3px 3px 3px;
}
#result
{
width:60px;
background:#33CC66;
color: #FFFFFF;
font-weight:bold;
}
</
style
>
<
script
>
function show()
{
var f = document.getElementById("f");
var s = document.getElementById("s");
var r = document.getElementById("result");
r.value = new Number(f.value) + new Number(s.value);
}
</
script
>
</
head
>
<
body
>
<
input
type
=
"text"
id
=
"f"
onkeyup
=
"show();"
/>+<
input
type
=
"text"
id
=
"s"
onkeyup
=
"show();"
/>
<
input
type
=
"text"
id
=
"result"
readonly
=
"true"
/>
</
body
>
</
html
>