The easiest way to do this is to use execCommand()
, which has a command to change the background colour in all modern browsers.
The following should do what you want on any selection, including ones spanning multiple elements. In non-IE browsers it turns on designMode
, applies a background colour and then switches designMode
off again.
UPDATE
Fixed in IE 9.
function makeEditableAndHighlight(colour) {
var range, sel = window.getSelection();
if (sel.rangeCount && sel.getRangeAt) {
range = sel.getRangeAt(0);
}
document.designMode = "on";
if (range) {
sel.removeAllRanges();
sel.addRange(range);
}
// Use HiliteColor since some browsers apply BackColor to the whole block
if (!document.execCommand("HiliteColor", false, colour)) {
document.execCommand("BackColor", false, colour);
}
document.designMode = "off";
}
function highlight(colour) {
var range, sel;
if (window.getSelection) {
// IE9 and non-IE
try {
if (!document.execCommand("BackColor", false, colour)) {
makeEditableAndHighlight(colour);
}
} catch (ex) {
makeEditableAndHighlight(colour)
}
} else if (document.selection && document.selection.createRange) {
// IE <= 8 case
range = document.selection.createRange();
range.execCommand("BackColor", false, colour);
}
}