php - 这个跳转哪里写的不对呢？

报这个错Parse error: syntax error, unexpected '' (T_ENCAPSED_AND_WHITESPACE), expecting identifier (T_STRING) or variable (T_VARIABLE) or number (T_NUM_STRING)

echo "<script>history.go(-1);location = 'blog3.php?id=$_POST['reid']';</script>";