<?php

header("Content-type:text/html;charset=utf-8");    //设置编码

$time1=date("Y-m-d H:i:s");                              //获取当前时间

$time2="2017-5-1 12:30:00";                              //给变量$time2设置一个时间

echo "变量\$time1的时间为：".$time1."<br/>";              //输出$time1的时间

echo "变量\$time2的时间为：".$time2."<br/>";              //输出$time2的时间

if(strtotime($time1)-strtotime($time2<0)){                   //对两个时间差进行差运算

    echo "\$time1早于\$time2";                              //time1-time2<0，说明time1的时间在前

}else{

    echo "\$time2早于\$time1";                              //否则，说明time2的时间在前

}

?>