Chapter 9

An event-driven, object-based programming language that provides various types of functionality to pages. Object based: it is a language that uses built-in objects that belong to the browser.

ObjectDescription ArrayReturns an ordered set of values BooleanConverts objects to Boolean values DateAccesses the system time and date DocumentRepresents the content of a browser's window FunctionAccesses information about specific functions HistoryKeeps track of Web pages visited locationSwitches to a new Web page MathPerforms calculations StringRepresents a set of characters WindowRepresents a browser window

attributes that describe an object's characteristics truck.style="pickup“ style=property, pickup = value

actions that an object can perform. truck.load() truck = object, load=method, () = arguement

value given to a method truck.load("firewood") firewood = describes material loaded into truck

Function: code that is written to perform certain tasks repeatedly Placed in the section of the HTML code User defined functions use generic tags to display dynamic information Container: tag that identifies a section of HTML code using the id attribute. Ex:

 Date() object access the current system date and time Can use 3 other methods to build a string for a a current date: getDate(), getMonth(), getFullYear()  Example: var sysDate=new Date() ; var sysDate=new Date(“February 12, 2014”)  new is a required keyword  2 nd example specifies a date for the sysDate variable

 To use the date and time, the variable must be converted to a string toLocaleString() method var variableName=dateString.toLocalString()  Example: Var curDate=sysDate.toLocaleString() curDate contains the date and time stored as Day of the Week Month Date Year HH:MM:SS

 Returns the positions of the first occurrence of a specified value in a string var position=strngValue.indexOf(“x”)  Example: curDate=“February 12, 2014” dateLocate=curDate.indexOf(“,”) Returns the position of the comma found in the string value of curDate: 11

 Uses 2 parameters (x,y) where x is the starting point of the string and y is the location of the last character needed. birthDay.substring(17,20) var variableName=string.substring(x,y)  Example: weekDay=dayofweek.substring(0,dateLocate) The variable weekDay containsf the substring result giving the current day of the week.

 Similar to substring() but differs in how it uses parameter values.  Example: var dayofweek=today.toLocaleString()  Converts date into string yearLocate=dayofweek.indexOf(“2014”) Year=dayofweek.substr(yearLocate,4)  The variable year contains the 4 digit year

 Can be used to store a future date. var variableName = new Date(“September 26, 2043”)

 Use the getTime() method of the Date() object  Returns the number of milliseconds that have elapsed since Jan. 1,  Must subtract the values to find the milliseconds. var variable = time1.getTime() – time2.getTime()

 Part of the Math() object  Used to round to the nearest Integer  To convert milliseconds to days, divide the number of milliseconds stored in the variable by the product of: 1000*60*60*24 var daysToExpo=Math.ceil(daysToGo/(1000*60*60*24))

 Allows dynamic content to be placed in the contained associated with the unique tag id.  Not recognized by Firefox!  Use the concatenate (+) sign to link elements tagId.innerHTML=“text string”+variable+”text string”

 A method of the document object  Form: document.getElementsByTagName(‘html’)  Example: styleObject= document.getElementsByTagName(‘html’)[0].style [0] represents which value you want returned, in an array format.

 Only works in IE!  Properties available: FaceColor, ArrowColor, HighlilghtColor, 3DlightColor, DarkshadowColor, TrackColor, and ShadowColor  Ex: styleObject.scrollbarFaceColor=“#ffde5b”

 Used with dropdown boxes  User selects an item in the list and the selectedIndex property returns the value of the item.  Items are “numbered” starting with 0.  Form: var Name=formName.SelectListName.selectedIndex

 Used to tell the browser where the new pages are located (linked in dropdown).  Form: object=window.location or window.location = URL Object = variable or other object that can display the URL URL = the address of the page to display

 lastModified Property displays the dte in the form of mm/dd/yyyy hh:mm:ss  Form: document.lastModified lastModified = property of the document object Ex: var lastModified = document.lastModified Could use: var lastModified =lastModified.substring(0,10) to only get date, not time.