I'am a newbie here trying to set a value of a hidden field on button click fetching value from a radio button. For some reason I'am able to alert the value but while assigning, it always gives me null.

Please help.

Thanks in advance.

<script type="text/javascript">
function deleteCheck(){
    var values = document.getElementById("deleteVisitID").checked;

        if (values) {
            var hiddenInput = document.getElementById('deleteIDValue');
            *hiddenInput.value=document.getElementById("deleteVisitID").value;* <---- throws error

            window.open("DeleteAppointmentSelected.jsp",'_self',false);
        }else{
            alert('Please Enter a ID before submitting');           
        }
}

</script>

on the form

<table border="1">
    <tr><th>visit_id</th><th>visit_date</th><th>visit_time</th><th>physician_id</th><th>Delete Visit</th></tr>
    <%
    while(visitsForPatient.next()){
        %><tr>
            <td>
                <% visit_id=visitsForPatient.getString(1);%>
                <%=visit_id %>
            </td>
            <td>
                <%visit_date=visitsForPatient.getString(2);%>
                <%=visit_date %>
            </td>
            <td>
                <%visit_time=visitsForPatient.getString(3);%>
                <%=visit_time %>
            </td>
            <td>
                <%physician_id=visitsForPatient.getString(4);%>
                <%=physician_id %>
            </td>
            <td>
<input type="radio" name="deleteVisitID" id="deleteVisitID" value="<%=visit_id %>"/>
            </td>


        </tr>

        <%

    }
    %></table><input type="hidden" name="deleteIDValue"/>

I'am a newbie here trying to set a value of a hidden field on button click fetching value from a radio button. For some reason I'am able to alert the value but while assigning, it always gives me null.

Please help.

Thanks in advance.

<script type="text/javascript">
function deleteCheck(){
    var values = document.getElementById("deleteVisitID").checked;

        if (values) {
            var hiddenInput = document.getElementById('deleteIDValue');
            *hiddenInput.value=document.getElementById("deleteVisitID").value;* <---- throws error

            window.open("DeleteAppointmentSelected.jsp",'_self',false);
        }else{
            alert('Please Enter a ID before submitting');           
        }
}

</script>

on the form

<table border="1">
    <tr><th>visit_id</th><th>visit_date</th><th>visit_time</th><th>physician_id</th><th>Delete Visit</th></tr>
    <%
    while(visitsForPatient.next()){
        %><tr>
            <td>
                <% visit_id=visitsForPatient.getString(1);%>
                <%=visit_id %>
            </td>
            <td>
                <%visit_date=visitsForPatient.getString(2);%>
                <%=visit_date %>
            </td>
            <td>
                <%visit_time=visitsForPatient.getString(3);%>
                <%=visit_time %>
            </td>
            <td>
                <%physician_id=visitsForPatient.getString(4);%>
                <%=physician_id %>
            </td>
            <td>
<input type="radio" name="deleteVisitID" id="deleteVisitID" value="<%=visit_id %>"/>
            </td>


        </tr>

        <%

    }
    %></table><input type="hidden" name="deleteIDValue"/>

• javascript
• html

• deleteIDValue isn't a id of any element – Tun Zarni Kyaw Commented Nov 27, 2013 at 8:08

2 Answers 2

<input type="hidden" name="deleteIDValue"/>

Needs to have an ID attribute:

<input type="hidden" name="deleteIDValue" id="deleteIDValue"/>

For this line in your script to work:

document.getElementById('deleteIDValue')

At the moment, you are trying to find an element with ID deleteIDValue which does not exist on the page. Therefore, you cannot call .checked or .value on a non-existent object, which is where you are getting the error.

This error is because you are declaring an object (array) and initialize in null value.

For example I got the same error because I was typing next incorrect code:

var employee = {obj: null};
employee.name = $("#txtnombre").val(); // this code is incorrect

The correct code is:

var employee = {obj: {}};
employee.name = $("#txtname").val();

Or

var employee = {name:null};