从HTML中的if语句调用Javascript函数

Question

This code is wriiten in VS 2003 -asp.net

in the HTML page, I have a javascript function checkuser() defined which returns boolean. I would like to enclose the following in a call to this function

<A onclick="stageClear(); stageEditor();" href="javascript: void(0);">Add new Stage</A>

I want something like

<%if checkuser() then%> <A onclick="stageClear(); stageEditor();" href="javascript: void(0);">Add new Stage</A> <% end if %>

But I am getting the error checkuser() not defined

Answer 1

Your code looks as if it is looking for an asp function called checkuser.

if you wanted to do it with js you would need to do something like this:

<script type="text/javascript">
   if (checkuser()) {
      document.write('<a onclick="stageClear(); stageEditor();" href="javascript: void(0);">Add new Stage</a>');
   }
</script>

Answer 2

If you intend to call the checkuser() function inside a server-side code block (as the one you show), you must define the function on the page's code behind, not on the client-side using JavaScript.

In other words, you need to have a function called

protected bool checkuser()
{
    return true;//just an example
}

And then you can call it as you intended to.

Answer 3

You can't mix your back end and your front end code.

<a onclick="clickHandler()" href="javascript:void(0)">Stuff</a>

and the JS:

<script>
    function clickHandler(){
        if(checkuser()){
            //do something
        }else{
            //do something else
        }
    }
</script>