The Window Object

The Window Object
Javascript the Definitive Guide by David Flanagan

CpSc 217 - Structured and Dynamic Web Programming

The notes found on these pages all reference the textbook given above. Unless otherwise stated, the citation of the information on these web pages is that text.

Timing

setTimeout(alert("hello world"), 2000); //milliseconds
setInterval(alert("hello world"), 1000); // alert every second

The browser consists of many objects. Some of these objects are discussed here.

The DOM can be easily examined using this page created by Dr. Dailey.

Navigator-appname, appVersion, platform
window object -window.open, status
document object (Yes, again!) - Lots of "stuff". We'll be back
form object -
Radio buttons, check boxes

Location Property

document.leocation or window.location
location property is the current URL of the document
location.assign("page.html") - makes window load and display the URL
location.replace("page.html") - makes window load and display the URL, but removes the current page from the history

window.location.href
permits browser to "change" to that page

URL

History Property

history.go(num);

1. window.history.back
2. window.history.forward
3. window.history.go Enter a positive or negative number to go forward or back	value

navigator Property

Used to determine browser used
navigator.appName - contains full name of web browser
"Microsoft Internet Explorer"

"Netscape"
navigator.appVersion - typically begins with a number then a string

Text Dialogs

alert() - pop a box up with a message
prompt() - prompt user for inpu
confirm() - pop up a box wait for ok to be clicked
showModalDialog() - permits html formatted code in dialog box. See page 350
window.onerror - message describing error that isn't handled

1. alert('hello world');
2. N=prompt('enter your name)'
3. confirm('you entered ' + a.value)

IDs of elements

document.getElementById("string") - gets the id "string"s HTML attribute
Example
Timer added
Add ability to click and bring up actor's name
document.getElementsByName("a") - tags that have name of "a"
```
var len=document.getElementsByName("a").length;
  for (i=0; i<len; i++ )
    document.write ("<br>Name A Tag " +i+" has value: " + document.getElementsByName("a")[i].value);
```
document.getElementsByTagName("INPUT") - show all input tags
```
var len=document.getElementsByTagName("INPUT").length;
  for (i=0; i<len; i++ )
    document.write ("<br>Input Tag " +i+" has value: " + document.getElementsByTagName("INPUT")[i].value);
```

Opening and closing browser windows

window.open() - create a new window
w= window.open()
w refers to new window (set location via w.location="url")

w2=window.open("put URL here", "put name here", "width=400,height=350,resizable="yes");
w2.alert("message for new window");
window.close() - close current window
w.close() - close new window from previous example

HTML elements

document.all
all elements have a page are placed in an array; they can be retrieved by indexing the array with the name of the element

This code produces the output
below the table.
Copy and paste the code into
a browser and change len to be document.all.length (Hmmmm....)

var len=document.all.length;
for (i=1; i<=len; i++ )
document.write ("<br>Tag " +i+" is: " + document.all[i].tagName);