## 1.try-catch ~~~ try{ alertt(1) }catch(err){ console.log(err.message) } //alertt is not defined ~~~ ## 2.throw ~~~ <script> var x = 1; try{ if(x==1) throw "x不能等于1" }catch(err){ console.log(err) } ~~~ ## 3.finally ~~~ var x = 1; try{ if(x==1) throw "x不能等于1" }catch(err){ console.log(err) }finally{ console.log("捕获异常结束") } ~~~