html select with different background color for every option that works properly in every browser?

Try this code, works in every browser including IE:

html

<select id="select1" onchange="colourFunction()">
<option class="white" value="A">This should have a WHITE background</option>
<option class="red" value="B">This should have a RED background</option>
<option class="yellow" value="C">This should have a YELLOW background</option>
<option class="green" value="D">This should have a GREEN background</option>
</select>

css

#select1 {width:150px; color:rgba(0, 0, 0, 0);}
#select1:focus, #select1:focus {
color:black;
}
.white {background:white;}
.red {background:red;}
.yellow {background:yellow;}
.green {background:green}

js

function colourFunction() {
var myselect = document.getElementById("select1"),
colour = myselect.options[myselect.selectedIndex].className;
myselect.className = colour;
myselect.blur(); //This just unselects the select list without having to click
somewhere else on the page
}

HTH :)