return - Javascript creating a new line on the html page? -

i have javascript function prints textboxes when user clicks button.

however when user clicks buttons multiple times textboxes go along page want on new line every time function called.

i tried this

x=document.write ('<br/>');            document.getelementbyid('txtara').appendchild(x) 

but clears page blank white.

thanks

document.getelementbyid ('txtara').innerhtml += '<br>';