backgroundColor not working

[BuildMyWeb]

javascript:

function highlight_field( field_name )
{
    alert(field_name);
    document.getElementsByName(field_name)[0].style.backgroundColor = 'yellow';
}

HTML form:

<form action='http://buildmyweb.org/testing/mfs/scripts/handler_register.php' method='post'>
<input class='req' type='text' placeholder='First Name' name="reg_f_name" />
<input class='req' type='text' placeholder='Last Name' name="reg_l_name" />
...
<input type='submit' name='submit_button' value='Register' id='reg_submit' />
</form>

when i load the page in question, the ALERT(); is triggering and displaying the correct value, 'reg_f_name'.  yet the background color of that field is not changing.  what am i doing wrong?

 

[scootstah]

Where are you calling highlight_field()?

[BuildMyWeb]

dzuh!  thank you scoot 

 

i was calling it prior to the form.  i suck with js.