Help With Using GetElementById()

I have this problem and when I came looking for help, I checked out the other thread like this but I couldn't get it to work. Here is the function -

PHP Code:

function newForm(focus, field)
{
    if ( focus == 'no' )
    {
        if ( document.getElementById(field).innerText == '' )
        {
            document.getElementById(field).innerText = '____________'
        }
    }

    if ( focus == 'yes' )
    {
        if ( document.getElementById(field).innerText == '____________' )
        {
            document.getElementById(field).innerText = ''
        }
    }
}


and here is the form -

PHP Code:

<b>Field 1:</b> <input type='text' name='field1' class='textbox' value='____________' onFocus="newForm('yes', 'field1')" onFocusOut="newForm('no', 'field1')" /><br /><br />
<b>Field 2:</b> <input type='text' name='field2' class='textbox' value='____________' onFocus="document.form.field2.innerText=''" onFocusOut="document.form.field2.innerText='____________'" /><br /><br />

field1 uses the function but field2 uses just onFocus and onFocusOut but as you can see, it won't work.