active server pages server-side scripting and client-side scripting
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Active Server Active Server PagesPages
Server-Side ScriptingServer-Side Scripting
andand
Client-Side ScriptingClient-Side Scripting
Key ConceptsKey Concepts
web serverweb server web applicationweb application request and responserequest and response server-side scriptingserver-side scripting client-side scriptingclient-side scripting ASP object modelASP object model
Client-Server RelationshipClient-Server Relationship
““It’s the Software, Stupid.”It’s the Software, Stupid.” a two-tier system...later a third tiera two-tier system...later a third tier the browser software is the clientthe browser software is the client the web server software is the serverthe web server software is the server http request — http responsehttp request — http response ASP request object — ASP response ASP request object — ASP response
objectobject three scenarios...three scenarios...
Scenario 1:Scenario 1:HTML OnlyHTML Only
browser browser requests requests page1.htm page1.htm with tags only, with tags only, no scriptno script
browser browser interprets tagsinterprets tags
server finds server finds page1.htmpage1.htm
server server downloads downloads page1.htm to page1.htm to clientclient
request
response
Client Server
Scenario 2:Scenario 2:HTML + JavaScriptHTML + JavaScript
browser browser requests requests page2.htm page2.htm with tags + with tags + JavaScriptJavaScript
browser browser interprets tags interprets tags + JavaScript+ JavaScript
server finds server finds page2.htmpage2.htm
server server downloads downloads page2.htm to page2.htm to clientclient
request
response
Client Server
Scenario 3:Scenario 3:HTML + ASP + VBScriptHTML + ASP + VBScript
browser browser requests requests page3.page3.aspasp with tags + with tags + ASP + VBScriptASP + VBScript
browser browser interprets tags interprets tags (only)(only)
server finds server finds page3.page3.aspasp, , passes to...passes to...
script engine, script engine, which which processes scriptprocesses script
server sends server sends pure HTML backpure HTML back
request
response
Client Server
Scripting LanguagesScripting Languages
JavaScriptJavaScript jointly developed by Sun and Netscapejointly developed by Sun and Netscape widely used on client-sidewidely used on client-side rollovers, pop-ups, forms testing, etc.rollovers, pop-ups, forms testing, etc. Microsoft version: JScriptMicrosoft version: JScript
VBScriptVBScript developed by Microsoftdeveloped by Microsoft based on Visual Basicbased on Visual Basic
Script EnginesScript Engines
each server-side script interpreted on each server-side script interpreted on the server at request timethe server at request time
Microsoft Internet Information Microsoft Internet Information Services 5.0Services 5.0 includes ASPincludes ASP includes VBScript engineincludes VBScript engine includes JScript engineincludes JScript engine
Identifying Server-Side Identifying Server-Side ScriptScript
using standard ASP delimitersusing standard ASP delimiters
using <script> tagsusing <script> tags
<body><body>
<h1>Welcome</h1><h1>Welcome</h1>
At Northeastern, the time is exactly <% = Time %>At Northeastern, the time is exactly <% = Time %>
</body></body>
<body><body>
<script language=vbscript runat=server><script language=vbscript runat=server>
Response.Write TimeResponse.Write Time
</script></script>
</body></body>
What happens to ASPs?What happens to ASPs?
web server looks for *.asp extensionweb server looks for *.asp extension passes to ASP Script Host (asp.dll)passes to ASP Script Host (asp.dll)
interprets all ASP codeinterprets all ASP code passes any scripts to appropriate enginepasses any scripts to appropriate engine puts pieces togetherputs pieces together passes back to web serverpasses back to web server
web server sends resulting HTML backweb server sends resulting HTML back
Some TerminologySome Terminology
Component>Object>MethComponent>Object>Methodod
think “Tool Chest > Tool Drawer > Tool”think “Tool Chest > Tool Drawer > Tool” A MethodA Method
an entity that DOES something useful (tool)an entity that DOES something useful (tool) An ObjectAn Object
neatly packaged box (drawer) of methodsneatly packaged box (drawer) of methods set of related functions and pieces of infoset of related functions and pieces of info
A ComponentA Component a package (chest) of related objectsa package (chest) of related objects
Our First Component (tool chest)Our First Component (tool chest)
The ASP 3.0 Object Model The ASP 3.0 Object Model (App. A)(App. A)
Request ObjectRequest Object Response ObjectResponse Object
Session ObjectSession Object Server ObjectServer Object Application ObjectApplication Object ASP Error ObjectASP Error Object
Client-SideClient-Side
Competitive TechnologiesCompetitive Technologies
JavaScriptJavaScript VBScriptVBScript Java AppletsJava Applets ActiveX ControlsActiveX Controls Dynamic HTMLDynamic HTML
Macromedia Flash ?Macromedia Flash ?
Server-SideServer-Side
Competitive TechnologiesCompetitive Technologies
CGI – Common Gateway InterfaceCGI – Common Gateway Interface ColdFusionColdFusion JSP – JavaServer PagesJSP – JavaServer Pages PHP – Personal Home PagesPHP – Personal Home Pages
Key ConceptsKey Concepts
web serverweb server web applicationweb application request and responserequest and response server-side scriptingserver-side scripting client-side scriptingclient-side scripting ASP object modelASP object model
Active Server Active Server PagesPages
Server-Side ScriptingServer-Side Scripting
andand
Client-Side ScriptingClient-Side Scripting