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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.


This section contains a variety of miscellaneous information.

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

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; }


Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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