Question

I have a table with rows in, and each row has a few <td> elements. The last element has a checkbox in.
They are in a <div> which is set to runat="server". I have another checkbox on the page called “chkAll” that when clicked, I want to javascript check or uncheck all of the checkboxes in my table.

I’m not very good at Javascript, so I am not sure what to do. I added a javascript onclick method, and put document.getelementbyid and put in the div.clientID, but I wasnt sure what to do from there. Any ideas?

Answer 1

once you have the the <div> element as a reference, use getElementsByTagName() to get the <input> elements, then check the type property, if it’s a checkbox then set it’s checked property the same as the checked property of the checkbox chkAll. For example

function toggleCheckBoxes(elem) {

    var div = document.getElementById('<% = divid.ClientID %>');

    var chk = div.getElementsByTagName('input');
    var len = chk.length;

    for (var i = 0; i < len; i++) {
        if (chk[i].type === 'checkbox') {
            chk[i].checked = elem.checked;
        }
    }        
}

and then attach this function as a click event handler of the chkAll element

<input type="checkbox" id="chkAll" onclick="toggleCheckBoxes(this)" />

Here’s a Working Demo. add /edit to the URL to see the code