Hi all, I developed a screen in which there are fields like first name,username,password and email. I validated these fields using javascript and came to know that javascript is not that safe. So i decided to validate on server side also. My question is whether i can use asp controls like requiredfieldvalidator, regularexpression validator to validate the form or i have to validate through server side coding??
Usually you can, it depends on how you implement the form, whether you use ASP.NET/SharePoint controls on it
You can definitely use asp controls like requiredfieldvalidator and regularexpression to validate your form. I've done this before.
Extra information
Thing to watch out for: If the page that you put these controls on is a publishing page, e.g. based on a custom layout page where editors can go in change content, the asp validator controls will still try to validate in 'Edit' mode. Therefore any SharePoint out of the box form submissions that added to the form will also trigger that the validation on your custom fields. In my case, I had a form on the page layout and some content fields, every time I edited the page, I couldn't save changes or publish until I filled out my form. The way around it is either, stick your validator controls in EditModePanels with the PageDisplayMode set to "Display":
<PublishingWebControls:EditModePanel ID="EditModePanel1" SuppressTag="true" runat="server" PageDisplayMode="Display"> Your validator control here </PublishingWebControls:EditModePanel>
or check for edit mode in the code behind on page load and turn the validators off from there.