Calculate VAT without doing a PostBack

[monkeymagic2222]

Hi,

I have 3 textboxes within a Details View, Unit Cost, VAT and Total.

All I want to do is, after a user has entered a figure into the Unit Cost to automatically calculate the VAT (unit cost * 17.5%) then populate the unit cost + VAT in the Total textbox.

Is this possible without doing a postback, i.e. maybe using something like JavaScript's OnChange?

Thanks in advance.

 

[ca8msm]

Yes, it will be fairly easy with javascript. Check out the forum here: forum216


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[dbsquared]

you could also put it into a update panel so that everything doesn't get posted back and do your calculation as normal.

To go where no programmer has gone before.

 

[blar9]

for textbox1:

txtbox1.Attributes.Add "onblur", "Calc()")

on asp page you would have:

<script type="text/javascript" language="javascript">

function Calc()
{
var value;
var Mins;

var = document.getElementById('<%=txtbox1.ClientID %>').innerText;

//do your math with the var then

document.getElementById('<%=txtbox2.ClientID %>').innerText = var;
}
</script>


is that what your looking for

 

[monkeymagic2222]

Hi blar9,

Yes thats pretty much what I was looking for. Using a combination of:

Page.ClientScript.RegisterClientScriptBlock and

CType(DetailsView1.FindControl("TextBox4"), TextBox).Attributes.Add("onblur", "return Calc();") I have achieved what I wanted.

Many thanks.