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Can any one please tell me how to validate a checkbox using javascript. Actually, my requirement is: the checkbox is to be checked only when a particular text box has been given a value. Until, the textbox is not filled, this checkbox is not allowed to be checked. Please tell me how can I implement this in my page.

Thanks in advance
Ankur\m/ 26-May-10 0:40am    
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Call this javascript function onClientClick of TextBox-

function DoTheCheck() {
if(document.myform.box1.checked == false)
{ document.myform.box1.checked = true;
; }


Nilesh Shah
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You'd need to break this down into a couple of steps

Your checkbox initial state should be disabled so the user can't simply click on it[^]

You then want to hook into the textbox 'onchange' event a have a function that validates the entry of the text box, making sure it's length > 0 or whatever your requirements are.

If it's OK, then enable the relevant checkbox and set it to checked.

In jQuery, this might read like

$(document).ready(function() {
    //JQuery keyup event
    $("#myTextBox").keyup(function() {
        var isValid = $(this).val().length > 0;
        $('#myCheckBoxItem').attr('checked', isValid )
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Create texbox
<asp:TextBox ID="TextBox1" runat="server" onblur="javascript:validate();"></asp:TextBox>

function validate()
    if(document.getElementById("TextBox1").value == checkValue)
        document.getElementById("CheckBox1").checked = true;

where checkValue is the value you want to check.

Hope this helps!
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