Javascrit Essential Training Part 3

Variable
Variable ဆိုတာ ပါ၀င္တဲ႔အရာေတြကိုဆိုလိုတာပါ

var year; 
var customerEmail;
var todaysDate;
var foo;
var x;

var 99problems;  အမွား
var problems99;     အမွန္

variable ကိုဖန္တီးျခင္း
var year;         ဒါက undefined မလုပ္ရေသးတဲ႔ year ပါ
year = 2012 ;    = နဲ႔ လုပ္ထားတဲ႔အတြက္ year တန္ဖိုးက 2012 ျဖစ္သြားပါျပီ
var year = 2012;

ေနာက္ျပီး variable name က case sensitive ျဖစ္ပါတယ္
အရင္တုန္းက Js ဟာ case sensitive ျဖစ္တယ္ဆိုတာေျပာခဲ႔ျပီးျပီ

 var x= 200 ;
 var X= 210;

 x ျခင္းတူေပးမယ္႔ စာလံုးအၾကီးအေသးမတူတဲ႔အတြက္ေၾကာင္႔ သူရဲ႕ value ေတြလည္းမတူညီပါဘူး

Variable data types

var myVariable; //undefined variable
var myVariable= 200; //200
var myVariable= "Hell0" ; //Hell0
var myVariable= 'Hello'; //Hello
var myVariable=true;  //True
var myVariable=false; //False

ကဲ႔ firefox ေလးဖြင္႔ျပီး firebug console ကိုဖြင္႔လိုက္ပါျပီးေတာ႔ ညာဖက္မွာ ေအာက္ကကုတ္ေလးကိုရိုက္ျပီး run ၾကည္႔ပါဦး

var foo=10;
var bar=20;

if(foo<bar){
    alert("foo is less than bar");
    alert("And here is second message");
    alert("And here is third message");
}

The Output is

ကဲ႔ result ကိုေတြ႔တယ္ေနာ္

console ပံုစံနဲ႔ေရးၾကည္႔ရေအာင္
var foo=10;
var bar=20;

if(foo<bar){
    console.log("foo is less than bar");
    console.log("And here is second message");
    console.log("And here is third message");
}

The Output is

ေနာက္အျခားေရးနည္း
1. console.debug

var foo=10;
var bar=20;
if(foo<bar){
    console.debug("cyberoot is here");
    //console.log(foo);
    //console.log(bar);
}

2.console.info
var foo=10;
var bar=20;
if(foo<bar){
    console.info("cyberoot is here");
    //console.log(foo);
    //console.log(bar);
}

3.console.warn
var foo=10;
var bar=20;
if(foo<bar){
    console.warn("cyberoot.blogspot.com");
    //console.log("And here is second message");
    //console.log("And here is third message");
}

4.console.error
var foo=10;
var bar=20;
if(foo<bar){
    console.error("cyberoot.blogspot.com");
    //console.log("And here is second message");
    //console.log("And here is third message");
}
ေအာက္္မွာၾကည္႔လိုက္ေနာ္ ဘယ္လိုအလုပ္လုပ္လဲဆိုတာ