JS report error - null object

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Hi,

This little piece of code got a mind of its own? The sky starts with Blue and when the Pink is click, it turns to pink ok, but when submit 'test' button to trun it to Dark, the JS keep reporting an error of Null object box1.

Any one can see what I did wrong, please give a hint please.

PS. where I can find a good reference for mixing JS, ASP aqnd html?

XML

<script language="javascript" type="text/javascript">
function putText(s) {
alert(s);
    document.f.box1.value = s;
    document.f.submit();
}
</script>

<body>
<%
box1 = request("box1")
if box1 = "" then
    box1 = "The sky is blue today"
    end if

if request("test") = "Dark" then
    response.Write("<script>putText('Submit to get dark sky')</script>")
    end if
%>

<form name="f" id="f" method="post">
<input name="box1" id="box1" type="text" value="<%=box1%>" />
<input type="submit" value="Pink" onClick="putText('Click to Pink Sky')"  />
<input name="test" type="submit" value="Dark"  />
</form>
</body>

rgds,
kfl.

Posted 19-Nov-10 17:31pm

KFLee

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Ankur^\m/ · Accepted Answer · 2010-11-19T23:22:00

The problem with your code is:
When you click the 'Dark' button, the JavaScript is called but the form and the other elements are not available at that time. So it gives an error: document.f.box1 is null or not an object.

To make this code working, move if request("test")... part to below dark button declaration.
I am giving you the working code below:

XML

<html>
<script language="javascript" type="text/javascript">
function putText(s) {
alert(s);
    document.f.box1.value = s;
    document.f.submit();
}
</script>
    <%
    box1 = request.form("box1")
    if box1 = "" then
        box1 = "The sky is blue today"
    end if
    %>
<body>
    <form name="f" id="f" method="post">
        <input name="box1" id="box1" type="text" value="<%=box1%>" >
        <input type="submit" value="Pink" onClick="putText('Click to Pink Sky')"  >
        <input name="test" id="test" type="submit" value="Dark"  >
        <%
        if request.form("test") = "Dark" then
            response.Write("<script>putText('Submit to get dark sky')</script>")
        end if
        %>
    </form>
</body>
</html>

Hope this solves the problem and clears your doubt.

[Edit]
And you don't even need to submit the form twice in the JavaScript function. So remove document.f.submit(); from the function.
[/Edit]