Show Alert in PreSaveAction after validation of Fields

Hi All,

i have a simple task, but I dont know the function call for this.

I want to show an alert in the PreSaveAction function after verifying that all Values in the Fields are valid.

So something like:

 function PreSaveAction() {               if (FieldsAreValid) {            
alert('<%=SPUtility.GetLocalizedString("$Resources:IdeaFactory,PopupTextEditIdeaDialog", null, SPContext.Current.Web.Language) %>');            
return true;       }   

 }

So my question is: Is there some fuction - FieldsAreValid -  like the PreSaveAction, that i can call in this manner?

Thank for any help

Martin