js中創(chuàng)建函數(shù)的三種方式:

第一種（函數(shù)聲明）：

function sum1(num1,num2){
   return num1+num2;
}
sum1(5,10);

第二種（函數(shù)表達(dá)式）：

var sum2 = function(num1,num2){
   return num1+num2;
}
sum(5,10);

第三種（函數(shù)對(duì)象方式）：

  var sum3 = new Function("num1","num2","return num1+num2");

  //var 函數(shù)名 = new Function(“參數(shù)...”,”函數(shù)體”);
  var sum = new Function("num1,num2","return num1+num2");
  var result1 = sum(120,130);
  alert(result1);