The idea is to create a set of “validation descriptors” associated with each element in a form.The “validation descriptor” is nothing but a string specifying the type of validation to be performed.Otherwise a browser with Java Script disabled, or a hacker trying to compromise your site, can easily submit invalid data. The first test in the example is therefore only necessary in order to provide a different error message when the input is blank.The purpose of a form validation script is to return a boolean value ('s to reference form fields, but that can lead to namespace conflicts and why make things more complicated than necessary.Validating form input with Java Script is easy to do and can save a lot of unnecessary calls to the server as all processing is handled by the web browser.
The problem is that, to have the data submitted in a 'nice' format to the server, the function returns an array containing all the selected checkbox values. In more complicated forms you will want to set conditions on the form that combine multiple elements.
The team at have made a video based on this article as a part of their Java Script training lessons which you can view below.
It explains some of the code examples above as well as introducing more advanced concepts: Very new to coding. Would be great if you could post full examples of code including form and not just pieces that fit into the greater framework of code.
When the form is submitted - either by hitting Enter or clicking on the Submit button - the (the 'value' of the field called 'input' belonging to the form). In a real-life situation you will most likely have more fields to check, and more complicated conditions, but the principle remains the same.
Other form values are available using a similar syntax, although this becomes more complicated if you're using SELECT lists, checkboxes or radio buttons (see below for examples). All you need to do is extend the command is encountered, execution of the function is halted.
In other words if the first condition fails, the second condition will not be tested and so forth.