Question

Again in problem
Actually I have following jsp code in which I have few text boxes which I have made disabled by using property disabled=”disabled”.
Now problem is each record that I will get from database in each text box using iterator which iterates values added from databse in arraylist.If database return more than one record then using that check box I can enable textboxes but if databse resultset return only one record then I am unable to enable textboxes and throws following ERROR:
Message: ‘document.f1.chk’ is null or not an object
Line: 26
Char: 10
Code: 0

<script type="text/javascript">

function enable()
{
    for(i=0;i<document.preapp.chk.length;i++)
        {
        if(document.preapp.chk[i].checked==true)

            {
            document.preapp.id[i].disabled=false;
            document.preapp.vname[i].disabled=false;
            document.preapp.comp[i].disabled=false;
            document.preapp.cont[i].disabled=false;
            document.preapp.wtm[i].disabled=false;
            document.preapp.intime[i].disabled=false;

            }
        else

            if(document.preapp.chk[i].checked==false)
            {
            document.preapp.id[i].disabled=true;
            document.preapp.vname[i].disabled=true;
            document.preapp.comp[i].disabled=true;
            document.preapp.cont[i].disabled=true;
            document.preapp.wtm[i].disabled=true;
            document.preapp.intime[i].disabled=true;
            }
        }
}


</script>

<CENTER><a href="../vm/form.jsp ">Back to Search</a></CENTER>
<form method="post" action="" name="preapp">

<table border="1" align="center" width="100%">
<%

Iterator itr;
try
{
ArrayList al=(ArrayList)request.getAttribute("sq");
int i=0;
for(itr=al.iterator();itr.hasNext();)
    {
i=i+1;


%>
        <tr>
            <td></td><td><input type="checkbox" name="chk"  onclick="enable(this)" ></td></tr></tr>
            <tr><td>Id</td><td><input type="text" name="id" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td>Visitor Name</td><td><input type="text" name="vname" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td>Comapny</td><td><input type="text" name="comp" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td>Contact</td><td><input type="text" name="cont" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td>Meeting Scheduled With</td><td><input type="text" name="wtm" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td>Entry Made On</td><td><input type="text" name="intime" value="<%=itr.next()%>" disabled="disabled" size="100%"></td></tr>
            <tr><td></td>
        </tr>

        <tr>


        </tr>

<%

    }

}
catch(Exception e)
{
e.printStackTrace();
System.out.println(e.getMessage());
}

%>

How Do solve this problem? please help me out!

Answer 1

It works like charm, except in the case you have only one TR block.

In that case, the .chk has no “length” attribute!

You should consider that case separately:

function enable()
{

    if(document.preapp.chk.length == null)
    {

        disabledState = !document.preapp.chk.checked

        document.preapp.id.disabled=disabledState;
        document.preapp.vname.disabled=disabledState;
        document.preapp.comp.disabled=disabledState;
        document.preapp.cont.disabled=disabledState;
        document.preapp.wtm.disabled=disabledState;
        document.preapp.intime.disabled=disabledState;

    } else {


        for(i=0;i<document.preapp.chk.length;i++)
        {

            disabledState = !document.preapp.chk[i].checked

            document.preapp.id[i].disabled=disabledState;
            document.preapp.vname[i].disabled=disabledState;
            document.preapp.comp[i].disabled=disabledState;
            document.preapp.cont[i].disabled=disabledState;
            document.preapp.wtm[i].disabled=disabledState;
            document.preapp.intime[i].disabled=disabledState;
        }
    }
}