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Learn how to write and call external JavaScript functions when working with JSON strings.

Table of contents

Preface

This module is one in a collection of modules designed for teaching ITSE 1356 Introduction to XML at Austin Community College in Austin, TX.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand the Listings while you are reading about them.

Figures

Listings

  • Listing 1 . Beginning of the file named Asg.htm.
  • Listing 2 . Call a function named objToStr.
  • Listing 3 . Call a function named strToObj.
  • Listing 4 . The HTML file named Asg.htm.
  • Listing 5 . The JavaScript file named Asg.js.

Preview

Previous modules in this collection have shown you how to transform JavaScript objects into JSON strings, and how to transform JSON strings intoJavaScript objects. Those program placed all of the JavaScript code in an HTML file. Sometimes you will need to break some of the JavaScript code outinto a separate file. You will learn how to do that in this module.

Discussion and sample code

This module will show you how to create an HTML file ( Asg.htm ) and a separate JavaScript file ( Asg.js ) containing functions that are called by JavaScript code in the HTML file. The JavaScript file will contain two functions:

  • A function named objToStr receives a JavaScript object as an incoming parameter and returns a JSON string that represents theobject.
  • A function named strToObj receives a JSON string as an incoming parameter and returns a JavaScript object that represents the string.

A complete listing of the HTML file is provided in Listing 4 near the end of the lesson. A complete listing of the JavaScript file is provided in Listing 5 near the end of the lesson.

Program output

Figure 1 shows the text that appears in a browser window when the files named Asg.htm and Asg.js are stored in the same folder and the file named Asg.htm is opened in a browser. Keep this figure handy so that you can refer to it while viewingthe code.

Figure 1 . Program output.
Display keys in object: name age Display values in object: Bill, 31Transform JavaScript object into a JSON string. In objToStrDisplay JSON string {"name":"Bill","age":31} Transform the JSON string into a JavaScript object.In strToObj Display values in object: Bill, 31Display keys in object: name age

Will explain in fragments

As is often the case, I will explain this program in fragments. The beginning of the file named Asg.htm is shown in Listing 1 .

Listing 1 . Beginning of the 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);

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Introduction to xml. OpenStax CNX. Dec 02, 2014 Download for free at https://legacy.cnx.org/content/col11207/1.18
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