javascript ѧϰ±Ê¼Ç£¨3£©
1. º¯ÊýÔÚÖ´ÐÐÍê return Ö¸Áîºó¾Í»áÍ£Ö¹Ö´ÐдúÂë.
function test(Num1,Num2){
return Num1+Num2;
alert(Num1+Num2); //never outputs
}
2. javascript º¯Êý²»ÄÜÖØÔØ,Ò²¾ÍÊÇ˵¿ÉÒÔÔÚͬһ¸ö×÷ÓÃÓòÖж¨Òå¶à¸öͬÃûº¯Êý,¶ø×îÖÕÖ´ÐеÄÊǺóÒ»¸öº¯Êý.
function test(num){
alert(num+10);
}
function test(num){
alert(num+100);
}
test(1); //outputs "101"
3. ÔÚº¯Êý´úÂëÖпÉÒÔʹÓÃÌØÊâ¶ÔÏó arguments È¡µÃûÓÐÃ÷È·Ö¸³öµÄ²ÎÊýÃû¾ÍÄÜ·ÃÎÊËûÃÇ.ͬʱ¿ÉÒÔʹÓà arguments.length »ñµÃ´«µÝ¸øº¯ÊýµÄ²ÎÊý¸öÊý.
function test(){
alert(arguments[0]);
}
test("hello"); //outputs "hello"
//----------------------------------
function testNum(){
alert(arguments.length);
}
testNum(12); //outputs "1"
testNum("hello",12); //outputs "2"
testNum(); //outputs "0"
4. º¯Êýʵ¼ÊÉÏÊǹ¦ÄÜÍêÕûµÄ¶ÔÏó. Function Àà.
5. º¯ÊýµÄ toString() ºÍ valueOf() ·½·¨·µ»ØµÄ¶¼ÊǺ¯ÊýµÄÔ´´úÂë.
6. javascript Ö§³Ö±Õ°ü.¼´º¯Êý¿ÉÒÔʹÓú¯ÊýÍⶨÒåµÄ±äÁ¿.
var test = "hello world";
function sayHelloWorld(){
alert(test);
}
sayHelloWorld(); //outputs "hello world";
var Num1 = 10;
function doAdd(Num2,Num3){
function doItAdd(){
return Num1+Num2+Num3;
}
return doItAdd();
}
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var b = new Array(8);
var c =
new Array("first", "second", "third");
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