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天蓬老师Correction status：qualified
Teacher's comments：图片加上标注非常好
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<script type="text/javascript">// 变量声明var num2 = 2;// 函数定义function myalert1( num2 ){if( typeof(num2) == 'undefined' ) {alert( 'num2未定义' );}else{alert( 'num2 = '+num2 );}}myalert1(num2);</script>
<script type="text/javascript">var myscore = 90;function func( ) {if( myscore >= 60 ){alert('合格');} else {alert('不及格');}}//func();var myscore = 69;function func2( ) {switch (true){case myscore >= 60:alert('合格');break;default:alert('不及格');}}// func2();var myscore = 59;function func3( ) {if( myscore >= 60 ){return alert('合格');}alert('不及格');}func3();</script>
<script type="text/javascript">// for循环function loop1(){for( var i=0; i<10; i++ ){console.log( 'i=' + i );}}// loop1();// while循环function loop2() {var flag = 10;while( flag > 0 ){flag--;if( flag == 6 ) continue; //跳过此次循环if( flag == 2 ) break; //跳出循环console.log( 'flag=' + flag);}}loop2();// do...while循环function loop3() {var flag = 10;do{flag--;console.log( 'flag=' + flag);}while( flag > 0 );}// loop3();</script>
<body><input type="text" id="username" value="" placeholder="请输入你的年龄"><button onclick="save()">提交</button><script type="text/javascript">function save() {var age = document.getElementById('username').value;age = parseInt( age );if( isNaN( age ) ){return alert( '年龄转换失败' );}alert( '你的年龄为' + age + '岁' );}</script></body>
