js_basics_2.html

<script>
	
/*
	alert(asdfgh); //It will throw error as 'asdfgh' is not declared anywhere on this script
	alert(myVariable); //this will show 'undefined' but does not throw ERROR. because 'myVariable' is set on line 68 
	
	
	var aVariableWithoutValue;	
	var aString = 'Hello';//anything enclosed by ''
	var anotherString = "Hi";//""
	var aNumber = 12;//	
	var aBoolean = true;//true
	var aVariableWithValueNull = null;
	var aStringLookLikeNumber = '12';
	var aStringLookLikeBoolean = 'true';
	var anEmptyString = "";	
	var aNaN = 12*'abc';	
	
	
	
	function aFunction(){
	
	};
	
	function anotherFunction(){
	
		return;
	};
	
	function anotherFunctionReturningNull(){
	
		return null;
	};
	
	
	
	try{
		var aUndefinedFromFunction = aFunction();
		var aUndefinedFromFunction2 = anotherFunction();
		var aNullFromFunction = anotherFunctionReturningNull();
		var aDiv = document.getElementById('myId');
		
		
		alert(//aVariableWhichIsnotDefined +"\n"+
			  typeof aVariableWithoutValue +" with a value :"+ aVariableWithoutValue +"\n"	+
			  typeof aString  +" with a value :"+ aString +"\n"+
			  typeof anotherString +" with a value :"+ anotherString +"\n"+
			  typeof aNumber +" with a value :"+ aNumber +"\n"+
			  typeof aBoolean +" with a value :"+ aBoolean +"\n"+
			  typeof aVariableWithValueNull +" with a value :"+ aVariableWithValueNull +"\n"+
			  typeof aStringLookLikeNumber +" with a value :"+ aStringLookLikeNumber +"\n"+
			  typeof aStringLookLikeBoolean +" with a value :"+ aStringLookLikeBoolean +"\n"+
			  typeof anEmptyString +" with a value :"+ anEmptyString +"\n"+
			  typeof aNaN +" with a value :"+ aNaN +"\n"+
			  typeof aUndefinedFromFunction +" with a value :"+ aUndefinedFromFunction +"\n"+
			  typeof aFunction +" with a value :"+ aFunction +"\n"+
			  typeof aUndefinedFromFunction2 +" with a value :"+ aUndefinedFromFunction2 +"\n"+
			  typeof aNullFromFunction +" with a value :"+ aNullFromFunction +"\n"+
			  
			  typeof aDiv +" with a value :"+ aDiv +"\n"
			  
			  
			 		  
		);
	}catch(e){
		alert(e.message+"\n"+e.name);
	}
	
	var myVariable = 'hi';
	alert(myVariable);
	
*/


	//type casting: Converting Data Type
	/*
	var aString1 = 'abc';
	alert(Number(aString1));
	
	var aString2 = '12';
	alert(typeof Number(aString2));
	
	var aNumber = 12;
	alert(typeof aNumber.toString());
	
	alert(Number('12abc')+"\n"+Number('abc12'));
	alert(parseInt('12abc')+"\n"+parseInt('abc12'));
	*/
	alert(parseInt('09'));
	
	
	
	
	
	
	
	
	
	

</script>