getSelection & surroundContents across multiple tags

Question

I've got a script that changes the background colour of text that has been selected. However i'm encountering an issue when the text is selected across multiple elements/tags.

The code that i've got is:

var text = window.getSelection().getRangeAt(0);
var colour = document.createElement("hlight");
colour.style.backgroundColor = "Yellow";
text.surroundContents(colour);

And the error being output is:

Error: The boundary-points of a range does not meet specific requirements. =
NS_ERROR_DOM_RANGE_BAD_BOUNDARYPOINTS_ERR
Line: 7

I believe this is to do with the getRange() function though i'm not too sure how to proceed since I am a beginner at javascript.

Is there any other way I can replicate what I am trying to achieve?

Many thanks.

Answer 1

This question has been asked today: How can I highlight the text of the DOM Range object?

Here's my answer:

The following should do what you want. In non-IE browsers it turns on designMode, applies a background colour and then switches designMode off again.

UPDATE

Fixed to work in IE 9.

function makeEditableAndHighlight(colour) {
    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);
    }
}