cindylu520

摘要： ""、0、null三个值用var_dump打印结果如下：string(0) "" int(0) NULL 用== 对其进行比较：if("" == 0){ echo "1<br />";}else{ echo "2<br />";}if("" == null){ echo "3<br />";}else{ echo "4<br />";}if(null == 0){ echo "5 阅读全文