？前为真就执行？号后面的，为假就执行：号后边的
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<script>
30>20?console.log(11111):console.log(22222)
10>20?console.log(11111):console.log(22222)
// ？前为真就执行？号后面的，为假就执行：号后边的
var sum = 210
var youhuisum = sum>200? sum-10 : sum
console.log(sum,youhuisum)
</script>
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