Validating length of textbox
Sometimes you have to validate information that doesn't come directly from an HTML form.A typical example is a page where a value is passed in a query string, as in the following example: source, including form-field values, query-string values, and cookie values.For example, if a page has an element as a placeholder for an individual field error, even if there is no error.In some situations, displaying an error message can cause the page to reflow and can cause elements on the page to move around.It's easy for people to change these values (perhaps for malicious purposes).So you must check these values in order to protect your application. This test would pass the first time that the page is requested, but not when the request is a form submission.The CSS rules that end in to both have the same fixed size.
For example, you don't want to process a form that's missing critical information.The length method counts how many characters are in a string and returns the number. Choose Visual Basic in installed templates, select ASP. This is useful for arrays or when validating a word has to be at least a minimum size. In that case, the validation is performed as users work in the browser.For example, suppose you specify that a value should be an integer.