Validation is one of the greatest security features to prevent your website against spam. We can do validation in two ways. One is from client-side and another is from server-side validation. Now here in this tutorial, I’ll explain how to proceed with dropdownlist validation from client-side using JavaScript in asp.net. In my previous tutorials, I’d explained how to validate dropdownlist using jquery, validate radiobuttonlist using javascript, validate checkboxlist using javascript and other more cracking tutorials on DropDownList, Asp.net here.