need to enable a button if the checkbox is enabled using javascript in aspx page

Question

need to enable a button if the checkbox is enabled using javascript in aspx page. Here is my code in aspx page. Please Help !

<script type="text/javascript">
function checkButt(obj) {
    alert("Inside the function");
    document.getElementById('<%=btnLoadForm.ClientID%>').disabled = !obj.checked;
}

Does the checkbox has autopostback set to true – Sushanth -- Nov 30 '12 at 21:11 — Sushanth --, Nov 30 '12 at 21:11

score 2 · Answer 1 · answered Dec 01 '12 at 09:11

Use following code you will get the solution.

Javascript

<script type="text/javascript">

    function enableordisable() {
            if (document.getElementById('CheckBox1').checked == true) {
                document.getElementById('Button1').disabled = false;
            }
            else {
                document.getElementById('Button1').disabled = true;
            }
    }

HTML

    <asp:CheckBox ID="CheckBox1" runat="server" Text="enable" onchange="enableordisable();" />
    <br />
    <br />
    <asp:Button ID="Button1" runat="server" Text="Button" Enabled="false" />

score 1 · Accepted Answer · edited May 23 '17 at 12:27

Instead of:

document.getElementById('<%=btnLoadForm.ClientID%>').disabled = !obj.checked;

You could try removing the disabled property from the element (add your logic as needed):

document.getElementById('<%=btnLoadForm.ClientID%>').removeAttribute("disabled")

Where disabled is a Boolean attribute, the value doesn't make much of a difference. You can read more on this in a similar post: HTML - Why boolean attributes do not have boolean value?

UPDATE:

You would need logic around the removeAttribute statement. Something similar to:

function checkButt(obj) {
    if(obj.checked)
      document.getElementById('<%=btnLoadForm.ClientID%>').removeAttribute("disabled");
}

This would enable document.getElementById('<%=btnLoadForm.ClientID%>') if obj.checked is checked.

@user1718398 - See if the update above makes things a bit more clear. — Chase, Dec 03 '12 at 18:02

score 0 · Answer 3 · answered Nov 30 '12 at 21:13

Remove the AutoPostBack="true" for the checkbox

Add the event in the script instead of inline HTML..

<asp:Button runat="server" id="btnLoadForm" />
<asp:CheckBox runat="server" id="chk" />

JS

var elem = document.getElementById('chk');

chk.addEventListener('click', function(){
    document.getElementById('btn').disabled = !this.checked;
});

Check Fiddle

need to enable a button if the checkbox is enabled using javascript in aspx page

3 Answers3