CODEWITHSUNDEEP
javascriptasp.nethtmlajax
SigmaOmega
SigmaOmega

Reputation: 31

Why reading a value from Label in Ajax doesn't work

I'm trying to read a value from a Label(asp) with Ajax. but i'm allways get Undefind :|

My Code is:

function NIS2USD() {
    var from = document.getElementById("NIS").value;
    var to = document.getElementById("USD").value;
    var amount = document.getElementById("totalAmountLabel").value;
    request = new XMLHttpRequest();
    request.onreadystatechange = ProcessResponse;
    request.open("GET", "Convert.aspx?from=" + num1 + "&to=" + num2 + "&amount=" +    amount, true);
    request.send();
}
function USD2NIS() {
    var from = document.getElementById("USD").value;
    var to = document.getElementById("NIS").value;
    var amount = document.getElementById("totalAmountLabel").value;
    request = new XMLHttpRequest();
    request.onreadystatechange = ProcessResponse;
    request.open("GET", "Convert.aspx?from=" + num1 + "&to=" + num2 +  "&amount="+amount, true);
    request.send();
}
function ProcessResponse() {
    if (request.readyState == 4 && request.status == 200) {
        document.getElementById("totalAmountLabel").innerHTML = request.responseText;
    }
}

and My def for the label is:

<asp:Label ID="totalAmountLabel" runat="server" Text="Label"></asp:Label>

Why I'm always getting undef?

Upvotes: 0

Views: 991

Answers (4)

Philip Badilla
Philip Badilla

Reputation: 1058

it is because controls get renamed when inside an update panel. try to use this if you have jQuery reference

$('#<%=totalAmountLabel.ClientID%>')

Upvotes: 1

Brian Mains
Brian Mains

Reputation: 50728

Either change the javascript to (the javascript code must be defined in page for this to work, not in a JS file because of the <%= %>):

 document.getElementById("<%= totalAmountLabel.ClientID %>").innerHTML = request.responseText;

Or leave the javascript as is and change the label to (for 4.0):

<asp:Label ID="totalAmountLabel" runat="server" Text="Label" ClientIDMode="static"></asp:Label>

Client ID mode of static ensures on the client the ID is actually totalAmountLabel

Upvotes: 0

gen_Eric
gen_Eric

Reputation: 227240

I assume <asp:Label> is generating an HTML <label> tag. If so, it doesn't have a .value attribute. Try .innerHTML instead.

var amount = document.getElementById("totalAmountLabel").value;

should be

var amount = document.getElementById("totalAmountLabel").innerHTML;

Upvotes: 0

Kapil Khandelwal
Kapil Khandelwal

Reputation: 16144

Try this to get the client ID for the label.

var amount = document.getElementById("<%=totalAmountLabel.ClientID%>").innerHTML;

Upvotes: 1

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