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代码块
<script type="text/javascript">
function test(){
var a = 12;
var b = 24;
console.log('number: ' + number); //undefined
return a + b; //return 后面的语句没有执行,但是会做词法分析
console.log( a + b );
var number = 12;
}
var c = test();
console.log( c );//36
</script>
执行顺序
- 词法分析期
a=undefined
b=undefined
number=undefined - 运行期:
赋值..
a = 12
b = 24
输出结果
number: undefined
36