Calendar expanded events by default is not working after migration to 2013

I have used below script in calendar to display 100 events expanded by default. it is working fine in share point 2010 after i have migrated this site to 2013 it shows "Unable to get property 'SummaryItemRenderer' of undefined or null reference" error.

_spBodyOnLoadFunctionNames.push('WaitForCalendarToLoad');

function WaitForCalendarToLoad() 
{   
    SP.UI.ApplicationPages.SummaryItemRenderer.prototype.$2u = function () 
    {
            ULSvSp: ;
            if (!this.$1A_1) this.$1A_1 = 3;
            return this.$1A_1
        }
}