s <- "...<span class=\"pull-right\">170 cm</span>...
<span class=\"pull-right\">29</span>...
<span class=\"pull-right\">06/24/1987</span>..."
m <- gregexpr("(?<=>)[0-9A-Za-z /]*(?=</span>)", s, perl=TRUE)
regmatches(s, m)
cyA8LSAiLi4uPHNwYW4gY2xhc3M9XCJwdWxsLXJpZ2h0XCI+MTcwIGNtPC9zcGFuPi4uLgo8c3BhbiBjbGFzcz1cInB1bGwtcmlnaHRcIj4yOTwvc3Bhbj4uLi4KPHNwYW4gY2xhc3M9XCJwdWxsLXJpZ2h0XCI+MDYvMjQvMTk4Nzwvc3Bhbj4uLi4iCm0gPC0gZ3JlZ2V4cHIoIig/PD0+KVswLTlBLVphLXogL10qKD89PC9zcGFuPikiLCBzLCBwZXJsPVRSVUUpCnJlZ21hdGNoZXMocywgbSkK