Question

Im trying to create a javascript function that sets the value of one input, when another one is changed. Heres my javascript (that isnt working):

<script type="text/javascript">
function addvalue(formname)

{
document.formname.elements.description.value = "filgerng";

}
</script>

And here are my two elements:

<input id="firstfile"  type="file" class="fileupload" name="files[]" size=
"80" onchange="addvalue(this.form)" />
<input id="firstdescription" type="text" name="description" size="50"
 />

Any ideas?

Answer 1

You have an error in your function at:

document.formname.elements.description.value = "filgerng";

Actually, elements is an array, use :

document.formname.elements[indexofthecontrol].description.value = "filgerng";

Plus, try to avoid this.form. This is not well handled by every browsers.

You’d better use a

document.getElementById('firstdescription').value="thisorthat";