Javascript technique 1



Array Function push, pop, shift, unshift 

myarr = [1,2,3,4];

return = myarr.pop();  // [1,2,3]    return 4
return = myarr.shift(); // [2,3]         return 1             

return = myarr.unshift(6); // [6,2,3]      return 6 
return = myarr.push(5);  // [6,2,3,5]     return 5
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Global vs local scope variable and functional variable

- Variable declared inside function  with var is local.
- Variable declared inside function without var is global.
- Variable declared outside function is  global.


var a =5; // global variable 

function() {

var b = 6;  // local functional variable
 c = 7;     // global variable  
}
console.log(a); //5
console.log(b); // undefined
console.log(c); // 7

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Escaping special character



\\         backslash \ 
\n        new line
\r         return -enter key like
\"         " as string
\'         ' as string
\t         tab 
\b         back space
\f          form feed

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Comparision Operator


2 == 2   // true

2 == '2'  // true

1 == true // true


Strict Comparision Operator

- also compare data type
2 === 2      // true 
2 === "2"   // false

1 === true  // false


Comprision with Inequlity Operator


2 != 2   // false
2 != "2"  // false
1 != true  // false


Comprision with Strict Inequlity Operator


2 !== 2     // true
2 !== "2"   // false
1 !== true  // true

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