Question

I am running this piece of code, for de-selecting a word a user selected in an iframe, when he selects another word outside the iframe:

function getCurrentWord() {
    var range;
    var w = "";

    if (document.selection) {
        ////IE
        range = document.selection.createRange();
        w = trim(range.text);
    } else {
        ////NOTIE
        w = trim(window.getSelection().toString());
    }

    if (w != "" && document.getElementById("frmBook")) {
        var oTextRange;
        if (document.selection) {
            ////IE
            oTextRange = document.getElementById("frmBook").contentWindow.document.selection.createRange();
            oTextRange.expand("word");
            oTextRange.execCommand("unselect") ;
        } else {
            ////NOTIE       
            oTextRange = document.getElementById("frmBook").contentWindow.getSelection();
            oTextRange.collapseToStart();
        }
    }

    if (w == "" && document.getElementById("frmBook")) {
        if (document.selection) {
            ////IE
            range = document.getElementById("frmBook").contentWindow.document.selection.createRange();
            w = trim(range.text);
        } else {
            ////NOTIE
            w = trim(document.getElementById("frmBook").contentWindow.getSelection().toString());
            /*
            IF I PUT IT HERE IT DOESN'T SHOW AN ERROR
            oTextRange = document.getElementById("frmBook").contentWindow.getSelection();
            oTextRange.collapseToStart();
            */
        }
    }
    return w;
}

The problem is i get this error on firefox error console:

Timestamp: 9/5/2012 12:20:42 μμ
Error: uncaught exception: [Exception… “An attempt was made to use an object that is not, or is no longer, usable” code: “11” nsresult: “0x8053000b (NS_ERROR_DOM_INVALID_STATE_ERR)” location: “http://192.168.0.88/test.js Line: 295″]

and that error occurs when the code is at the

oTextRange.collapseToStart();

line.

I tried to run it in a single line like this :

document.getElementById("frmBook").contentWindow.getSelection().collapseToStart();

but i get the same error

frmBook is the ID of the iframe

IF i run that piece of code which causes the error where I have commented it out, it doesn’t show an error and that’s weird!

Anybody knows what am I doing wrong ?
Thanks in advance

Answer 1

Looking at (what may possibly be an old version of) the source code at http://dxr.lanedo.com/mozilla-central/layout/generic/nsSelection.cpp.html it seems that collapseToStart will produce that error if nothing is actually selected. You could check whether oTextRange.rangeCount is < 1, and simply not do the collapse if so. (If there’s some reason why that should be impossible, then you probably have a different problem.)