这个脚本到底在做什么？ 试图了解JavaScript

Question

<script type="text/javascript">    
                var limitNum = 100;    
                var message = 'You are not able to type more than ' + limitNum + ' symbols!';    

                function checkLength(validator, args)    
                {    
                    var editor = <%=editortextbox1.ClientID%>;     // get a reference to RadEditor
                    var editorText = editor.GetText(true);     //get the HTML content of the control
                    args.IsValid = editorText.length > limitNum && editorText.length < 15;    
                }    
            </script>     

is this script checking if editortextbox1 is empty or not ? if not, what is it doing? Also, if I do want to check that editortextbox1 is empty or not, how should I modify this script. Oh and what if I want this script to run for ALL the Textboxes on my page, what change do i need to make then?? Like I have 2-3 Text boxes(which are actually RadEditors). I want to check for null values in all the editors. How should I modify this script??

Answer 1

It's ensuring that the editortextbox1 field has less than 15 characters, and more then than 100...meaning it can never be valid. It seems like it should be:

args.IsValid = editorText.length <= limitNum && editorText.length >= 15;

to be a valid check.

Answer 2

The script defines two variables and a function. It does not check anything.

When the function is executed, it sets args.IsValid to false . This is because editorText.length > 100 && editorText.length < 15 is always false .

Answer 3

currently args.IsValid will be always false:

editorText.length > limitNum && editorText.length < 15;

nothing can be greater than 100 and less than 15. Anyway i believe that this function was currently meant to return the validity of the length of certain Textbox (probably to check a minimum and maximum length), anyways the script itself doesn't do anything, but the code that calls this function does.