JS之形参带默认值的写法代码
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<meta charset="UTF-8">
<title>JS之形参带默认值的写法代码</title>
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<script>
function c(x, y){
//console.log(y); //结果：undefined或者值
if(y == undefined){
y = 3; //如果调用函数时，没有传递第二个参数y的值，那么让y=3
}
console.log(x + y); //结果：5 6
}
c(2);
c(2, 4);
</script>
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