Question

I have this jQuery method which works fine if I am on a page where there are elements found which have class .singlePaneOfGlassBlock.

function replaceRightClickIcefacesMethod() {
        //I only want this to run on IE for now, but the content 
        //is prepared to run on other browsers too
        if (jQuery.browser.msie) {
            var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                    .attr("oncontextmenu"), fn = String;

            //IE returns function instead of string so let's try to take the string
            //in the right way
            if (typeof oldName == "function") {
                oldName = elem[0].getAttributeNode("oncontextmenu").value,
                        fn = Function;
            }
            //do the replace
            oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                    'contextMenuPopupUpdated');
            //change oncontextmenu with the new value
            jQuery.each(elem, function() {
                this.setAttribute("oncontextmenu", fn(oldName));
            })
        }
    }

But it failes with this error:

`'undefined' is null or not an object`

on the line where it tries to do the replace if I am on other pages where those type of elements are missing…

I have add a checking to see if it’s null or if it contains that string before doing the replace, but it still fails:

if (jQuery(oldName).length || oldName.indexOf("Ice.Menu.contextMenuPopup") != -1) {
        oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                'contextMenuPopupUpdated');
        jQuery.each(elem, function() {
            this.setAttribute("oncontextmenu", fn(oldName));
        })
    }

Can you give me a solution?

Thanks.

UPDATE: when I’m asking a solution I’m just asking on how to correct this method to not run when that type of elements are not found?

Answer 1

Update: Re your updated code in the question:

function replaceRightClickIcefacesMethod() {
    if (jQuery.browser.msie) {
        var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                .attr("oncontextmenu"), fn = String;

        if (typeof oldName == "function") {
            oldName = elem[0].getAttributeNode("oncontextmenu").value,
                    fn = Function;
        }

        // ====> This is where the bug is, you're assuming you have
        //       a string at this point, but you don't necessarily,
        //       because if there is no match at all, `attr` will
        //       return `undefined` or `null` (I forget which).
        //do the replace
        oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                'contextMenuPopupUpdated');
        //change oncontextmenu with the new value
        jQuery.each(elem, function() {
            this.setAttribute("oncontextmenu", fn(oldName));
        })
    }
}

to fix:

function replaceRightClickIcefacesMethod() {
    if (jQuery.browser.msie) {
        var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                .attr("oncontextmenu"), fn = String;

        if (typeof oldName == "function") {
            oldName = elem[0].getAttributeNode("oncontextmenu").value,
                    fn = Function;
        }

        // ====> Add this `if`:
        if (oldName) {
            //do the replace
            oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                    'contextMenuPopupUpdated');
            //change oncontextmenu with the new value
            jQuery.each(elem, function() {
                this.setAttribute("oncontextmenu", fn(oldName));
            });
        }
    }
}

---

Original answer:

It seems to me you’re missing some braces (at least):

function replaceRightClickIcefacesMethod() {
if (jQuery.browser.msie) {
    var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
            .attr("oncontextmenu"), fn = String;
    if (typeof oldName == "function") { // <=== Added { here
        oldName = elem[0].getAttributeNode("oncontextmenu").value,
                fn = Function;

        oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                'contextMenuPopupUpdated');
        jQuery.each(elem, function() {
            this.setAttribute("oncontextmenu", fn(oldName));
        })
    } // <=== Added } here
}
}

Here’s the above with the indentation corrected:

function replaceRightClickIcefacesMethod() {
    if (jQuery.browser.msie) {
        var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                .attr("oncontextmenu"), fn = String;
        if (typeof oldName == "function") { // <=== Added { here
            oldName = elem[0].getAttributeNode("oncontextmenu").value,
                    fn = Function;

            oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                    'contextMenuPopupUpdated');
            jQuery.each(elem, function() {
                this.setAttribute("oncontextmenu", fn(oldName));
            })
        } // <=== Added } here
    }
}

Here’s your original with the indentation corrected:

function replaceRightClickIcefacesMethod() {
    if (jQuery.browser.msie) {
        var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                .attr("oncontextmenu"), fn = String;
        if (typeof oldName == "function")
            oldName = elem[0].getAttributeNode("oncontextmenu").value,
                    fn = Function;

        // Note how these statements are NOT protected by the `if`
        // above, and so if `oldName` is `undefined` (as opposed to
        // being a String or Function.
        oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                'contextMenuPopupUpdated');
        jQuery.each(elem, function() {
            this.setAttribute("oncontextmenu", fn(oldName));
        })
    }
}

Or it may be that you’re missing an else clause and probably a further defensive if:

function replaceRightClickIcefacesMethod() {
    if (jQuery.browser.msie) {
        var elem = jQuery(".singlePaneOfGlassBlock"), oldName = elem
                .attr("oncontextmenu"), fn = String;
        if (typeof oldName == "function") {
            oldName = elem[0].getAttributeNode("oncontextmenu").value,
                    fn = Function;
        }
        else {    
            oldName = oldName.replace('Ice.Menu.contextMenuPopup',
                    'contextMenuPopupUpdated');
        }
        if (oldName) {
            jQuery.each(elem, function() {
                this.setAttribute("oncontextmenu", fn(oldName));
            });
        }
    }
}

But it’s really hard to say, I can’t quite follow the logic. The function path part of it doesn’t seem to change anything, but the string path part does…