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$init = $_GET['score']; switch($init){ case $init >=90 : echo '
厉害了，我的学霸！
'; break; case $init >=80 : echo '
再接再厉，努力吧！
'; break; case $init >=70 : echo '
差太多啦！得加油赶上了！！
'; break; case $init >=60 : echo '
建议你留级吧！！
'; break; default: break; }

Obviously no parameters have been passed to the form yet, so how come the first case is output? At this time, the $init variable is empty. How can it be judged successful? ? What's going on? ?