Question

83

Set Text property of asp:label in Javascript PROPER way

rated 0 times [ 85] [ 2] / answers: 1 / hits: 129610 / 12 Years ago, thu, april 12, 2012, 12:00:00

I have a series of textboxes on a form. When the user inserts numbers into these textboxes, calculations are made and <asp:Label> controls are updated via JavaScript to reflect these calculations:

document.getElementById('<%=TotalLoans.ClientID %>').innerHTML = TotalLoans;

This correctly updates the UI. However, when I try to access the value in the codebehind, the Text property is empty. This makes sense I guess, since I was updating the innerHTML property via the JavaScript.

//TotalLoans.Text will always be equal to  in this scenario

double bTotalLoans = string.IsNullOrEmpty(TotalLoans.Text) 

                   ? 0.00 

                   : Convert.ToDouble(TotalLoans.Text);

How do I update the Text property of the <asp:Label> via JavaScript in such a way that I can read the property in the codebehind?

Update

This is a small problem on a large form that contains 41 labels, each of which displays the results of some calculation for the user. Taking the advice of FishBasketGordo I converted my <asp:Label> to a disabled <asp:TextBox>. I'm setting the value of the new textbox as such:

    document.getElementById('<%=TotalLoans.ClientID %>').value = TotalLoans;

Again, in the codebehind, the value of TotalLoans.Text is always equal to .

I don't mind changing how I approach this, but here's the crux of the matter.

I am using JavaScript to manipulate the property values of some controls. I need to be able to access these manipulated values from the code behind when 'Submit' is clicked.

Any advice how I can go about this?

Update 2

Regarding the answer by @James Johnson, I am not able to retrieve the value using .innerText property as suggested. I have EnableViewState set to true on the <asp:Label>. Is there something else I am missing?

I don't understand why, when I type in a textbox and submit the form, I can access the value in the codebehind, but when I programmatically change the text of a textbox or label by way of JavaScript, I cannot access the new value.

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juliettec

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3 Years ago

answered 12 Years ago admin · Accepted Answer

Place HiddenField Control in your Form.

<asp:HiddenField ID=hidden runat=server />

Create a Property in the Form

protected String LabelProperty

{

    get

    {

        return hidden.Value;

    }

    set

    {

        hidden.Value = value;

    }

}

Update the Hidden Field value from JavaScript

<script>

   function UpdateControl() {

            document.getElementById('<%=hidden.ClientID %>').value = '12';

   }

</script>

Now you can access the Property directly across the Postback. The Label Control updated value will be Lost across PostBack in case it is being used directly in code behind .