Jquery datepicker problem on date select in IE – ‘length’ is null or not an object

I am posting a wonderful post on Jquery datepicker.
Because I am using Jquery in ASP.NET application, I added a regular expression for date to validate whether user entered date is valid or not. Because of adding the validation on the text box, whenever I select a date from datepicker, the datepicker events are firing like onselect, change etc.. So, generally what validation framework is doing, whenever some event fires on the page, validations will execute. The same thing happening here. Whenever I change or select date from the date picker, it will fire some events and at the same time validation framework trying to validate the validations. But, it is not the right event to do validations. So, always we will get the exception at “vals.length” in a for loop of the built-in code. vals is the object of all the validators on the page. It always fails to load in Jquery date picker event trigger, because it is not the right event for validation. And the result is vals is undefined, you always get exception at vals.length as “length is null or not an object”. I think now you got very clear idea of why it is happening. Now, move to the next step i.e. solution for it.

Solution is very simple, I read all the documentation of Jquery datepicker and found an event named onSelect. So, whenever I select date this is the event firing. So, there I got a clue and started thinking towards it. And below is the result.

$(“.datepicker”).datepicker({ onSelect:function(){}});

In your datepicker initialization statement add onSelect event which don’t do anything means empty function as shown above. There problem solved. Isn’t a good find? Please let me know your thoughts on this.

Ref : praveenbattula

Using jQuery validation in a sharepoint web part

As we all know, a SharePoint page can only have one <form > tag in it. As anyone who wanted to use jQuery validation knows, the validation script needs to run on a form tag.
So how do I use the validation code in a sharepoint web part?

The answer is to run the script against the form that already exists in the page. For example, I had to write a web part with an email address field, and wanted to help the users by validating the text they entered is a valid email address on the client side (I also validate on the server side – just in case someone is running a browser with no script). This is the “Render” override code that I used:

txtEmailAddress1.CssClass = “required email”;

       base.Render(writer);
       if (SPContext.Current.FormContext.FormMode != Microsoft.SharePoint.WebControls.SPControlMode.Edit)
       {
              writer.Write(@"<script>
$().ready(function() {
    $(""#" + this.Page.Form.ClientID + @""").validate();
});
</script>
");
       }

As you can see, I am adding a css class of type “required email” for the text box, and then telling the form on the page to validate using the jquery validation plug in. This of course assumes you added the references to the jquery scripts to the page…which you may want to do as part of the web part (override oninit, and registerclientscriptblock) or as part of the master page (if you expect a lot of web parts to use it).

As for the “if (SPContext.Current.FormContext.FormMode != Microsoft.SharePoint.WebControls.SPControlMode.Edit)” line – you have to be careful that your validation does not prevent you from editing the page. For example, if you remove that “if”, you will not be able to change the properties of any web part on the page without first entering a valid email address in the textbox!

Ref : Sharepoint Tips And Tricks