simple javascript nightmare

[techtimmy]

Hopefully really easy for someone with even a basic understanding of javascript.

I've 'written' a function which collects the info from a form field:

var justhow;
function calculate(select)
{
justhow = document.forms[0].howmany.value;
}

When i try to call the bugger later on

document.write('<input type="text" name="total" size="10" value="' + justhow + '">');

it comes back as undefined.


I know it works fine as if I move the document.write into the function it does the calculation (but in a new page?!?!?)

I thinkits something to do with global/local variables but after reading about 50 different tutorials its still not working.

Can anyone help?

Thanks

 

[StudioVision]

Hi

This should help:

var justhow;
function calculate(){
justhow = document.getElementById('howmany').value;
document.getElementById('total').value = justhow;
}

Then in your page you would need the following form fields:

<input type="text" id="howmany" size="10" value="" onkeyup="javascript:calculate(this.value)">
<input type="text" id="total" size="10" value="">

Whenever the value of field id "howmany" is changed, the value of field id "total" will be updated.

Hope this helps!

Craig

 

[techtimmy]

Awesome skillz dude.

Many many thanks

 

[StudioVision]

No worries, glad it helped!