Sharepoint Form Validation using Javascript

Sharepoint Form Validation using Javascript

1.First open the Newform.aspx which you want to validate.(go to list and go to "New item" page)

2.then add ?PageView=Shared&ToolPaneView=2 part at the end of the urlEx: http://mysite/Lists/job/NewForm.aspx
http://mysite/Lists/job/NewForm.aspx?PageView=Shared&ToolPaneView=2
3. Add "Content editor web part " and modify this web part with source editor option
4. Add following javascript which use to validate start date & due date

5. Now use it...

6. If you want to use javascript to validate other field just put following script and modify it as you wish.. 

<Script language="javascript">
function PreSaveAction()
{
//add your JavaScript code here and return true / false
}

</Script>