JavaScript

What Might Need To Be Validated?

• String
• Number
• Date
• Time
• Zip Code
• URL
• E-mail Address
• Credit Card
• Salary
• etc.

Validation

• Can locate one error at a time or all errors.
• Can be server-side or client-side or both.
• One good technique is to perform client-side validation and then to have the server-side revalidate. This cuts down on network traffic, but also maintains control over unreliable client-side scripts or client environments.

JavaScript Uses

• Client-Side Validation
• Add Dynamic Functionality to Webpage (e.g. show running total)
• Add Dynamic Elements to Webpage (e.g. mouse rollover)
• Use Information from Browser to Enhance Presentation
• General Tip: Use JavaScript for simple tasks and use PHP for complex tasks.

Learning JavaScript

• W3 Schools

Some Difference From PHP

• Variables are not prefixed by $
• Local variables must be declared
• Different opening and closing script tags are required
• String concatenation uses the + sign
• There is a for ... in loop instead of a foreach loop

Events

• onblur, onchange, onfocus
• onclick
• onload, onunload
• onmouseover, onmouseout
• onreset
• onsubmit

Objects

• navigator
  • properties : platform, userAgent
• window
  • properties: location.href, name, locationbar.visible, menubar.visible, personalbar.visible, scrollbars.visible, statusbar.visible, toolbar.visible, status
  • methods: alert(), back(), close(), confirm(), forward(), open(), print(), prompt()
• document
  • properties : lastModified, title, URL
  • methods: write() and writeln() --- writeln() outputs a single space after it is finished, but write() does not. To see the difference try document.write("hi"); document.writeln("hi"); document.write("hi");
• form
  • properties: name, action, method
  • methods: submit(), reset()
• form elements such as select, textarea, input, button
  • properties: type, value, value.length, name
  • methods: focus(), blur(), select(), charAt()

Lecture Example

• form.html
• verify.js
• continue.php5