I'm doing software development for SharePoint 2013. Part of this involves overriding SharePoint's file previewer (filepreview.debug.js bees myfilepreview.debug.js). We've run into problems, however, with IE8. Everything works just fine in IE9.

The error thrown in IE8 causes an error on any site you visit within the site collection that our custom feature is activated on: "Object does not support this property or method"

After doing some research on this error, it would appear that IE8 simply does not support Object.create. This Mozilla Developer post seems to support this theory. I was more pressed to believe this when the issue was solved by adding this polyfill code before the line that was throwing the error:

if (typeof Object.create !== 'function') {
    Object.create = function (o) {
        function F() { }
        F.prototype = o;
        return new F();
    };
}

I guess that would make sense that it works because it mimics the functionality of Object.create which supposedly isn't supported in IE8.

However, this was confusing because SharePoint's file previewer javascript works just fine. Their javascript also uses Object.create. Even weirder, the section of code that was throwing the error in our javascript wasn't even our code -- it's SharePoint's. The entire javascript code up to then is actually the same as SharePoint's as well, except for a few lines.

Here's the default, up to the line in question:

function $_global_filepreview() {
RegisterSod("mediaplayer.js", "_layouts/15/mediaplayer.js");
RegisterSod("sp.publishing.resources.resx", "/_layouts/15/ScriptResx.ashx?name=sp.publishing.resources&culture=" + STSHtmlEncode(Strings.STS.L_CurrentUICulture_Name));
RegisterSodDep("mediaplayer.js", "sp.publishing.resources.resx");
previewBase = (function() {
ULS7RK:
    ;
    var filePreviewUniqueId = 0;

    return {
        init: function(ctxT, listItem, extension) {
            this.fpId = ++filePreviewUniqueId;
            this.fpDomId = "FilePreviewID-" + String(this.fpId);
            this.fpCtx = ctxT;
            this.fpExtension = extension;
            this.fpListItem = listItem;
        },
        getHtml: function() {
        ULS7RK:
            ;
            return ['<div class="js-filePreview-containingElement" id=', StAttrQuote(this.fpDomId), '>', this.getInnerHtml(), '</div>'].join("");
        },
        getDomId: function() {
        ULS7RK:
            ;
            return this.fpDomId;
        },
        getContainingElement: function() {
        ULS7RK:
            ;
            var containingElement = document.getElementById(this.fpDomId);

            Sys.Debug.assert(m$.isElement(containingElement), "Containing element has not been rendered yet.");
            return containingElement;
        },
        canRender: function() {
        ULS7RK:
            ;
            return true;
        },
        getLoadingIndicatorHtml: function(customStyle) {
            if (m$.isUndefined(customStyle)) {
                customStyle = "";
            }
            return ['<div class="js-filePreview-loading-image" style="width:', this.getWidth(), 'px; height:', this.getHeight(), 'px; line-height:', this.getHeight(), 'px; text-align:center; vertical-align:middle; display: inline-block; ' + customStyle + '">', '<img src="', "/_layouts/15/images/gears_anv4.gif", '" />', '</div>'].join("");
        },

        hideLoadingIndicator: function() {
        ULS7RK:
            ;
            var containingElement = document.getElementById(this.fpDomId);

            ((m$(containingElement)).find("div.js-filePreview-loading-image")).css({
                display: "none"
            });
        },

        getInnerHtml: function() {
        ULS7RK:
            ;
            return "";
        },
        getWidth: function() {
        ULS7RK:
            ;
            return null;
        },
        getHeight: function() {
        ULS7RK:
            ;
            return null;
        },
        onPostRender: function() {
        },
        onVisible: function() {
        },
        onHidden: function() {
        }
    };
})();
//**This is where the "fix" was added originally**
blankPreview = Object.create(previewBase); <--- error is thrown here

The only difference between the SharePoint javscript (above) and ours (up to this point) is we've removed these following two lines from the beginning, though adding them back still doesn't solve the issue:

RegisterSod("sp.publishing.resources.resx", "/_layouts/15/ScriptResx.ashx?name=sp.publishing.resources&culture=" + STSHtmlEncode(Strings.STS.L_CurrentUICulture_Name));
RegisterSodDep("mediaplayer.js", "sp.publishing.resources.resx");

So my question is: Why am I getting this error that Object.create isn't supported in IE8 while other uses of the same exact function in the default javascript work without issue?

EDIT: A user on another forum suggested I try registering my script via sod. I added this to my code without effect:

RegisterSod("MyFilepreview.debug.js", "_layouts/15/MyFilepreview.debug.js");

I'm doing software development for SharePoint 2013. Part of this involves overriding SharePoint's file previewer (filepreview.debug.js bees myfilepreview.debug.js). We've run into problems, however, with IE8. Everything works just fine in IE9.

The error thrown in IE8 causes an error on any site you visit within the site collection that our custom feature is activated on: "Object does not support this property or method"

After doing some research on this error, it would appear that IE8 simply does not support Object.create. This Mozilla Developer post seems to support this theory. I was more pressed to believe this when the issue was solved by adding this polyfill code before the line that was throwing the error:

if (typeof Object.create !== 'function') {
    Object.create = function (o) {
        function F() { }
        F.prototype = o;
        return new F();
    };
}

I guess that would make sense that it works because it mimics the functionality of Object.create which supposedly isn't supported in IE8.

However, this was confusing because SharePoint's file previewer javascript works just fine. Their javascript also uses Object.create. Even weirder, the section of code that was throwing the error in our javascript wasn't even our code -- it's SharePoint's. The entire javascript code up to then is actually the same as SharePoint's as well, except for a few lines.

Here's the default, up to the line in question:

function $_global_filepreview() {
RegisterSod("mediaplayer.js", "_layouts/15/mediaplayer.js");
RegisterSod("sp.publishing.resources.resx", "/_layouts/15/ScriptResx.ashx?name=sp.publishing.resources&culture=" + STSHtmlEncode(Strings.STS.L_CurrentUICulture_Name));
RegisterSodDep("mediaplayer.js", "sp.publishing.resources.resx");
previewBase = (function() {
ULS7RK:
    ;
    var filePreviewUniqueId = 0;

    return {
        init: function(ctxT, listItem, extension) {
            this.fpId = ++filePreviewUniqueId;
            this.fpDomId = "FilePreviewID-" + String(this.fpId);
            this.fpCtx = ctxT;
            this.fpExtension = extension;
            this.fpListItem = listItem;
        },
        getHtml: function() {
        ULS7RK:
            ;
            return ['<div class="js-filePreview-containingElement" id=', StAttrQuote(this.fpDomId), '>', this.getInnerHtml(), '</div>'].join("");
        },
        getDomId: function() {
        ULS7RK:
            ;
            return this.fpDomId;
        },
        getContainingElement: function() {
        ULS7RK:
            ;
            var containingElement = document.getElementById(this.fpDomId);

            Sys.Debug.assert(m$.isElement(containingElement), "Containing element has not been rendered yet.");
            return containingElement;
        },
        canRender: function() {
        ULS7RK:
            ;
            return true;
        },
        getLoadingIndicatorHtml: function(customStyle) {
            if (m$.isUndefined(customStyle)) {
                customStyle = "";
            }
            return ['<div class="js-filePreview-loading-image" style="width:', this.getWidth(), 'px; height:', this.getHeight(), 'px; line-height:', this.getHeight(), 'px; text-align:center; vertical-align:middle; display: inline-block; ' + customStyle + '">', '<img src="', "/_layouts/15/images/gears_anv4.gif", '" />', '</div>'].join("");
        },

        hideLoadingIndicator: function() {
        ULS7RK:
            ;
            var containingElement = document.getElementById(this.fpDomId);

            ((m$(containingElement)).find("div.js-filePreview-loading-image")).css({
                display: "none"
            });
        },

        getInnerHtml: function() {
        ULS7RK:
            ;
            return "";
        },
        getWidth: function() {
        ULS7RK:
            ;
            return null;
        },
        getHeight: function() {
        ULS7RK:
            ;
            return null;
        },
        onPostRender: function() {
        },
        onVisible: function() {
        },
        onHidden: function() {
        }
    };
})();
//**This is where the "fix" was added originally**
blankPreview = Object.create(previewBase); <--- error is thrown here

The only difference between the SharePoint javscript (above) and ours (up to this point) is we've removed these following two lines from the beginning, though adding them back still doesn't solve the issue:

RegisterSod("sp.publishing.resources.resx", "/_layouts/15/ScriptResx.ashx?name=sp.publishing.resources&culture=" + STSHtmlEncode(Strings.STS.L_CurrentUICulture_Name));
RegisterSodDep("mediaplayer.js", "sp.publishing.resources.resx");

So my question is: Why am I getting this error that Object.create isn't supported in IE8 while other uses of the same exact function in the default javascript work without issue?

EDIT: A user on another forum suggested I try registering my script via sod. I added this to my code without effect:

RegisterSod("MyFilepreview.debug.js", "_layouts/15/MyFilepreview.debug.js");

• c#
• javascript
• sharepoint
• internet-explorer-8
• sharepoint-2013

Share Improve this question Follow edited Jan 27, 2013 at 18:30 Pavlo 45k1414 gold badges8383 silver badges114114 bronze badges asked Jan 21, 2013 at 14:19 tnwtnw 13.9k1515 gold badges7171 silver badges114114 bronze badges 7

• 1 Well the Sherlock Holmes thing to do would be to conclude that one of those two lines is causing a similar shim to be imported into the page. Of course, if that were true, failure after adding the lines back (resulting in you having exactly the same code) would make no sense. Thus, one might question that assertion: are those really the only differences? – Pointy Commented Jan 21, 2013 at 14:21
• @Pointy A very valid question indeed. I've double and triple checked and it it really is the only difference up to that point. – tnw Commented Jan 21, 2013 at 14:35
• The sharepoint server may do browser sniffing, and thus return different JS file for different browsers. Did you save this javascript code with IE8 or with a different browser (or did you find it on the server side)? – molnarg Commented Jan 23, 2013 at 16:20
• @molnarg Interesting suggestion, though I've confirmed that this code is exactly the same for both IE8 and IE9. I found it using F12 debugging. Additionally, I've pulled up the file in the 15 hive on the server and confirmed it is also the same file there. – tnw Commented Jan 23, 2013 at 16:25
• @tnw try substituting Object.create with a simple new previewBase(). Does that throw the same error? – Jibi Abraham Commented Jan 30, 2013 at 12:12

 |  Show 2 more ments

2 Answers 2

Sorted by: Reset to default 3

Try debugging in IE and put breakpoints in SharePoint's default JavaScript file. Are you sure the instances of Object.create in the default JavaScript are actually being hit?

They aren't using Object.create with proper arguments.

They use Object.create({name:value}) when it should be Object.create({name:{value:value}}).

So they probably defined their own Object.create and their code is used after yours so you already have your Object.create set when their code runs and they probably test for existence just like you do and assume it's their version that is there when in fact it's yours.

So check for a definition of Object.create in their code and check the order in which scripts are executed.