how to call a javascript function in content page from aspx page itself

<asp:Content ID="head" ContentPlaceHolderID="headcontent" Runat="Server">

function func1()
{
alert('the code i want to bind to dropdownlist ');
}
window.onload=func1
function func2()
{
alert('hai');
}
this is not working 
even this is also not working
window.onload=fun_onload()
{
func1()
}