Limit the size of a TextArea in Detailview

How can i limit the size of a TextArea field in the detailview?

because when the text is too long, it push the whole right size out of the browser:

i tried to limit it through the view.detail.php file ,using javascript,  but the field is actually a span inside a table so it doesn't work.

also tried through the detailviewdefs.php file using :

'displayParams' =>
array (
'size' => '51',

but it doesn't work although not sure limiting a default size is the right solution.

i'm using CE version 6.5.13

can anyone help? 

thank you:)