Question

Is it possible to set transparency of any image in javascript?
And how can I do that?

Answer 1

If using plain javascript this should work:

function SetOpacity( imageid, opacity ) {
    var s= document.getElementById(imageid).style;
    s.opacity = ( opacity / 100 );
    s.MozOpacity = ( opacity / 100 );
    s.KhtmlOpacity = ( opacity / 100 );
    s.filter = 'alpha(opacity=' + opacity + ')';
}

Call by: SetOpacity('myImg', 50); //Half transparent

Source here