how to get a list's add new item URL with JSOM?

Question

I'm trying to figure out how I can get a list's add new item URL using JSOM in SharePoint 2010. This is what I have so far to get if the current user has edit access on the list.

ExecuteOrDelayUntilScriptLoaded(function()
{
    var clientContext = SP.ClientContext.get_current();
    var list = clientContext.get_web().get_lists().getByTitle("Shared Documents");
    clientContext.load(list);
    clientContext.load(list, 'EffectiveBasePermissions');
    clientContext.executeQueryAsync(Function.createDelegate(this, function()
    {
        if(list.get_effectiveBasePermissions().has(SP.PermissionKind.editListItems))
        {
            // has edit permissions
        }
    }), Function.createDelegate(this, function(){}));
}, "sp.js");

Answer 1

Load DefaultNewFormUrl property of the list. Example:

clientContext.load(list, 'DefaultNewFormUrl');

Then retrieve it in the success method:

var newUrl = list.get_defaultNewFormUrl();

Answer 2

I guess your are looking for SP.List.defaultNewFormUrl property (sp.js).

var value = SP.List.get_defaultNewFormUrl();

Try following

var list = clientContext.get_web().get_lists().getByTitle("Shared Documents");
var listNewForm = list.get_defaultNewFormUrl();

PS: MSDN documentation reads that

Applies to:

apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013

I think it should work in SharePoint 2010 also. Try and let me know.