Dhtml is a mixture of javascript and css where we can set the style of an element using CSS then change it using javascript.
Unfortunately the syntax varies slightly between the way CSS sets properties and the way Javascript does it.
This is a common source of errors for new dhtml programmers
For example, to set the background colour of a span using a style sheet command the code is
<span id='fred' style='background-color:orange;'>Some text</span>
If we then wish to change the background colour using javascript, say in response to some event, we must write
document.getElementById('fred').style.backgroundColor='blue'
Note the change from the stylesheet background-color to the javascript backgroundColor
This syntax change pretty much applies to most properties.
With Javascript the Stylesheet dashes, -, are removed and an Uppercase letter is used.