remove trailing br
var regex = /^\s*(?:<br\s*\/?\s*>)+|(?:<br\s*\/?\s*>)+\s*$/gi,
string = ' <br /><br /><br/ >this is <br /><br /><br/ > a test<br /><br /><br/ ><br> ';
string = string.replace(regex, ''); //changed replacement
console.log(string);