try catch throw用法
var x = prompt("Enter a number between 0 and 10:","") try { if (x > 10) { throw "Err1"; } else if (x < 10) { throw "Err2"; } } catch(er) { if (er == "Err1") { console.log("Error! The value is too high"); } if (er == "Err2") { console.log("Error! The value is too low"); } }