JS syntax

JS syntax

1. variables

   • boolean
     • flag var
   • string
     • toLowerCase( )
       • converts all the characters to lower case
     • toUpperCase( )
       • converts all the character to upper case
     • lastIndexOf( )
       • finds last instance of the segment (gives number location)
     • indexOf( )
       •  the method finds the index of the first character of the segment  (gives index location)
     • charAt( )
       • finds (and asign to another variable) the single character of index at the string (specify variable index) can only identify character by specific location.
     • replace( )
       • string replacing in the first instance of segment /string/g this is global replacing for all met instances
   • Numbers
     • parseInt ( )
       • converts strings including floatings to integer and also cut floatings to integer
     • parseFloat( )
       • convert floating strings to floating number
     • Number
       • Converts "numbered"string to integer or floating strings to floating point numbers
     • toString( )
       • converts number to string
     • toFixed(n)
       • controlling the length of decimal. "n" in the brackets specifies decimal point for floating number and convert them to strings. some browser round down!.
     • Math.round( )
       • rounds floating number to the nearest Integer
     • Math.ceil( )
       • round up to the nearest Integer
     • Math.floor( )
       • rounds to the lower Integer
   • Arrays
     • pop( )
       • removes the last element of array
     • push( )
       • adds one or more elements to the end of array
     • shift( )
       • removes element from the beginning of the array
     • unshift( )
       • add one or more elements to the beginning of the array
     • splice( )
       • to insert one or more elements anywhere in array ... optionally remove one or more elements that come after it
     • slice( )
       • to copy one or more consecutive elements in any position ... and put them into a new array

2. popup windows

   • alert ( )
   • prompt( )

3. logic

   • comparison operator
     • === == !=== !== < > <= >=
   • if else
   • conditions
     • && II
   • ternary conditions
     • var age = 26; var beverage = (age >= 21) ? "Beer" : "Juice"; // "Beer"
   • if .. if else
   • nested if

4. counters

   • maths expressions
     • num++
       • incremented post it means added +1 after signing of to variable
     • ++num
       • incremented prior increased value before assigning to variable
     • num--
       • decremented post minus 1 after signed to variable
     • --num
       • decremented prior minus 1 before signing to variable
   • for loop

5. Date & Time

   • getDay( )
     • get days in the number 0-6, starting from Sunday
   • getMonth( )
     • gets numbers 0-11 , starting from January
   • getDate( )
     • gets number 0-31, 1 is 1st day of the month
   • getFullYear( )
   • getHours( )
     • 0 - is midnight  12 - is soon
   • getMinutes( )
     • in the range of 0-59
   • getSeconds( )
     • gets seconds in the range of 0-59
   • getMilliseconds( )
     • get milliseconds in the range 0-999
   • getTime( )

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