$a='<script type="text/javascript" src="http://bbs.tp.h/api/uc.php?time=1461895011&code=cad8LdOmZPd1JcqW7tOsBZf6XVgrftQf9WF1gQ8%2F79bszHQa4yvRtGWNBr78r9I3wxdtlz6WRmTqRp23m0eyzO0xzOCpjvIcaiLixCdooGrx54XAn3xPmGnZbKNbS%2B5cScy%2FOrTpw1bEnUx0qPJT79Pe0V48RdijXu0" reload="1"></script><script type="text/javascript" src="http://tp.h/api/uc.php?time=1461895011&code=c107qcxqqAROR%2F6X15nGwNNVYw9kqxNzeNkgXnsPj75GGPH5oh9E%2FlAEB%2F%2BOp7E7yo1dQv%2FBzHnHRZGiFz43ovyZSPeD7gsTLDzBkbZtV6JxPhCfJExBxYVdjUn62Bdm8fa9ScS3PEIgs%2Fhj96SI4eK8oTHzccPs33Y" reload="1"></script>'
php正则表达式如何得到上面字符串中的src的值?