Quick Reference - JavaScript

Number Object¶

Method	Description
`num.toFixed(x)`	Rounds off the number to `x` places after the decimal point

String Object¶

Functions¶

Adapted from here.

Method	Description
`s.charAt()`	Returns the character at the specified index
`s.charCodeAt()`	Returns the Unicode of the character at the specified index
`s.concat()`	Joins two or more string, returning a copy of the joined strings
`s.fromCharCode()`	Converts Unicode values to characters
`s.indexOf()`	Returns the position of the first occurrence of a specified value in a string
`s.lastIndexOf()`	Returns the position of the last occurrence of a specified value in a string
`s.match()`	Searches for a match between a regex and a string, returning the matches
`s.replace()`	Searches for a match between a substring/regext and a string, replacing the matched substring with a new substring
`s.search()`	Searches for a match between a regex and a string, returning the position of the match
`s.slice()`	Extract a part of a string and returns a new string
`s.split()`	Splits a string into an array of substrings()
`s.substr()`	Extracts the characters from a string from a start position and length
`s.substring()`	Extracts the characters from a string between two specified indices
`s.toLowerCase()`	Converts a string to lowercase
`s.toUpperCase()`	Converts a string to uppercase
`s.valueOf()`	Returns the primitive value

Extensions¶

String.prototype.startsWith = function(prefix, caseSensitive) {

	if (caseSensitive == undefined) caseSensitive = true;
	
	if (caseSensitive)
		return (this.substr(0, prefix.length) == prefix);		
	else
		return(this.substr(0, prefix.length).toUpperCase() == prefix.toUpperCase());
    
}
String.prototype.contains = function(searchFor, caseSensitive){

    if (caseSensitive == undefined)
        caseSensitive = true;
        
    if (caseSensitive)
        return (this.indexOf(searchFor) >= 0);
    else    
        return (this.toUpperCase().indexOf(searchFor.toUpperCase()) >= 0);
        
}