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The only new code in Listing 1 is the fifth line, which declares that afile named Asg.js contains JavaScript code that may be called by JavaScript code in the HTML file. Otherwise, the code in Listing 1 simply creates a JavaScript object and displays its contents. You have seen codelike that before.

Call a function named objToStr

The second statement in Listing 2 is new to this module. This statement calls a JavaScript function named objToStr passing the JavaScript object as a parameter.

Listing 2 . Call a function named objToStr.
document.write("<br/>Transform JavaScript object " + "into a JSON string.");var jsonstring = objToStr(obj01);

When the JavaScript interpreter encounters this statement, it searches the current file ( Asg.htm ) for a function having that name. When it doesn't find the function in the current file, itsearches the file named Asg.js , which was declared in Listing 1 . It finds the function in that file (see Listing 5 ) and executes it.

The function named objToStr

The code in the function named objToStr is straightforward. You have seen code like this before. After announcing that it has been called,the objToStr function calls the JSON.stringify method to create and return a JSON string based on the contents of theJavaScript object.

Call a function named strToObj

Returning to the code in the file named Asg.htm , the third statement in Listing 3 calls a function named strToObj passing the JSON string as a parameter.

Listing 3 . Call a function named strToObj.
document.write( "<br/>Display JSON string " + jsonstring );document.write("<br/>Transform the JSON string " + "into a JavaScript object.");var obj02 = strToObj(jsonstring);

The function named strToObj is also shown in Listing 5 . The code in this function is also straightforward and you have seen codelike this before. The strToObj function calls the JSON.parse method to create and return a JavaScript object based on the contents of the JSON string.

Following that, the code in the file named Asg.htm simply displays the contents of the JavaScript object. You can view that code in Listing 4 .

Run the program

I encourage you to copy the code from Listing 4 and Listing 5 and execute it by opening the HTML file in your browser. Experiment with the code,making changes, and observing the results of your changes. Make certain that you can explain why your changes behave as they do.

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Json0140-External JavaScript Functions
  • File: Json0140.htm
  • Published: 11/02/14
Disclaimers:

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

Complete program listings

Complete listings of the HTML file and the JavaScript file are shown below.

Listing 4 . The HTML file named Asg.htm.
<!DOCTYPE html><html><head><title>ITSE 1356</title><script type='text/javascript' src='Asg.js'></script></head><body><script>var obj01 = {name:"Bill",age:31}; document.write("<br/>Display keys in object: "); for (var key in obj01) {if (obj01.hasOwnProperty(key)) { document.write(key + " ");}//end if }//end for loopdocument.write("<br/>Display values in object: "); document.write(obj01.name + ", " + obj01.age);document.write("<br/>Transform JavaScript object " + "into a JSON string.");var jsonstring = objToStr(obj01);document.write( "<br/>Display JSON string " + jsonstring );document.write("<br/>Transform the JSON string " + "into a JavaScript object.");var obj02 = strToObj(jsonstring);document.write("<br/>Display values in object: "); document.write(obj02.name + ", " + obj02.age);document.write("<br/>Display keys in object: ");; for (var key in obj02) {if (obj02.hasOwnProperty(key)) { document.write(key + " ");}//end if }//end for loop</script></body></html>
Listing 5 . The JavaScript file named Asg.js.
function objToStr(obj){ document.write("<br/><br/>In objToStr<br/>"); var str = JSON.stringify(obj);return str; }function strToObj(str){ document.write("<br/><br/>In strToObj<br/>"); var obj = JSON.parse(str);return obj; }

-end-

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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