how to pass selected item from listbox of one form to text box of other form

how to pass selected item from listbox of one form to text box of other form in javascript and html

i call given given below function setpara() in onchange event of listbox control

function setpara()
{
//alert('Hey I said not to try clicking this link');

document.form11.t1.Value=document.f1.cns_1.getSele ctedValue;
document.form11.t2.Value=document.f1.cns_2.getSele ctedValue;


}

here t1 and t2 are textbox names

and cns_1 and cns_2 are listbox names

and f1 and form11 are form names



but stilll this code is not work

what to do...now

chintan