Is there a color code for transparent in HTML?

There is not a Transparent color code, but there is an Opacity styling. Check out the documentation about it over at developer.mozilla.org

You will probably want to set the color of the element and then apply the opacity to it.

.transparent-style{

    background-color: #ffffff;
    opacity: .4;

}

You can use some online transparancy generatory which will also give you browser specific stylings. e.g. take a look at http://www.css-opacity.pascal-seven.de/

Note though that when you set the transparency of an element, any child element becomes transparent also. So you really need to overlay any other elements.

You may also want to try using an RGBA colour using the Alpha (A) setting to change the opacity. e.g.

.transparent-style{
    background-color: rgba(255, 255, 255, .4);
}

Using RGBA over opacity means that your child elements are not transparent.

#0000ffff - that is the code that you need for transparent. I just did it and it worked.

When you have a 6 digit color code e.g. #ffffff, replace it with #ffffff00. Just add 2 zeros at the end to make the color transparent.

Here is an article describing the new standard in more depth: https://css-tricks.com/8-digit-hex-codes/

All you need is this:

#ffffff00

Here the ffffff is the color and 00 is the transparency

Also, if you want 50% transparent color, then sure you can do... #ffffff80

Where 80 is the hexadecimal equivalent of 50%. Since the scale is 0-255 in RGB Colors, the half would be 255/2 = 128, which when converted to hex becomes 80

And since in transparent we want 0 opacity, we write 00