Step towards SharePoint

 I just added some basic components like  TextBox ,  RequiredfieldValidator , and validation summary controls only. Its shows the following error Adding the following element in  web.config   <appSettings> <add key = "ValidationSettings:UnobtrusiveValidationMode" value = "None" /> </appSettings>

http://msdn.microsoft.com/en-us/library/office/dn268594(v=office.15).aspx

EnabledScript = " javascript:var EnableDisable=function(){             this.clientContext=SP.ClientContext.get_current();             this.selectedItems=SP.ListOperation.Selection.getSelectedItems(this.clientContext);             var ci = CountDictionary(selectedItems);             return (ci == 1);             };EnableDisable(); " Hope this will helps you............

I was struggling to get my custom images loaded for use on my custom ribbon action that I defined in my SharePoint Hosted App for SharePoint 2013. so, you could use name of the application instead of ~appWebUrl