php去除HTMLl和空格截取中文乱码

$CourseList[0]['about'] = strip_tags($CourseList[0]['about']);

$CourseList[0]['about'] = preg_replace ('/\n/is', '', $CourseList[0]['about']);

$CourseList[0]['about'] = preg_replace ('/ |　/is', '',$CourseList[0]['about']);

$CourseList[0]['about'] = preg_replace ('/ /is', '', $CourseList[0]['about']);

$title = mb_substr($CourseList[0]['about'],0,6,"UTF8");

$content = mb_substr($CourseList[0]['about'],6,113,"UTF8");