Develop Reference

Correlating a Row with Column on Javascript

I currently have a table with a function that checks certain columns that have checkboxes, whenever they are "clicked off", to see if they're all completely empty.
The function does a loop from the first of the checked columns up until the last one that has to be checked. They go from 1 to 8, and their ids go from "f01_check" up until "f08_check". If all are empty, it adds a css class to its description column that changes background color.
The function looks like this:
function unChecked(rowNumber) {
alert(rowNumber);
var i = 1;
var check = false;
// Column loop
while (i < 9 && check == false) {
if (rowNumber.getElementById("f0" + i + "_check").checked == false) {
i++;
} else {
check = true;
}
// If all checkboxes are empty, add class
if (i == 9 && check == false) {
$s(description.addClass(emptyRecords));
}
}
}
The Dynamic Action leading to this function and its parameter is this:
var row = this.triggeringElement.closest('tr');
unChecked(row);
I realize that the rowNumber.getElementById doesn't work, but I can't figure out how to link or connect them. The way I'm looping through the columns might be a rough attempt, but it works. I've tested it on a set column and it it does stop whenever the loop reaches a checked checkbox. The problem is I just can't dynamically set the row to match the one that I've clicked.
I've tried getting the property .rowIndex as well, but I can't figure out where to use it, even if I do get the correct value.

I found a different solution, that also somewhat solves a different problem in the future.
Rather than use rownum to set a dynamic id for the columns, I changed it to it's primary key:
apex_item.checkbox (1, '1_' || pk, decode(data1,null,null,'CHECKED'), null, null, 'f01_' || pk) as lpb1
This basically helped me on knowing which row was being clicked, because the id also held it's primary key. This allowed me to use it's primary key value to improve the function. The item_pkis an item that gets its value from the corresponding table column:
function unChecked(row) { // var row = this.triggeringElement.closest('tr').rowIndex;
// unChecked(row);
var i = 1;
var check = false;
while (i < 9 && check == false) {
if (document.getElementById("f0" + i + "_" + item_pk.value).checked == false) {
i++;
} else {
check = true;
}
if (i == 9 && check == false) {
//addClass Segment
}
}
}
So if the report were to be filtered, the row number wouldn't match what the filter actually showed on the report table.
The previous solution was also fixed by removing the case clause from the select, as follows:
apex_item.checkbox (1, '1_' || a.pk, case when max(decode(data1,1,1,null)) is null then '' else 'CHECKED' end, null, null, 'f01_chk') as lpb1,
But again, the first solution showed actually foresees and handles a filtered report, so I believe it's a superior and more accurate solution.
Now I just need to complete the addClass segment. For some reason Apex is setting the field "static id" as the column header, which is slightly problematic since I meant to use the document.getElementById. But at least the main problem has been fixed. Thanks for the responses.

Creating and overwriting variables dynamic per user input

In the following code, the user is able to create variables utilizing the window object via an input type text element. I've written a function that console logs the name of the variable followed by the value of 0 in which the variable is initialized. This only occurs when the following key string literal, "-nr " precedes the desired name for the created variable.
The goal of this exercise is to increment any created variable value by 1 when the variable name is reentered into the input element. My attempt at doing so is by first writing the first function, varCreate to declare and initialize variables to 0, push them into an array, and console log the variable name followed by its value. The next function which I have a problem with (varPlus) is meant to add 1 to the value of each value when a particular name is entered into the input element however, it adds a few more than 1 even when I utilize a for loop to evaluate if the string literal value of the input element value property is equivalent to each element of the array varArray.
const _in = document.getElementById('in');
var varArray = [];
function varCreate(e) {
let _key = e.key;
if(_key === "Enter") {
if(_in.value.substring(0, 4) == "-nr ") {
window[_in.value.substring(4).replace(/\s/g, "_")] = 0;
varArray.push(_in.value.substring(4).replace(/\s/g, "_"));
console.log("var: " + varArray[varArray.length - 1] + "\nvalue: " + window[varArray[varArray.length - 1]]);
_in.value = "";
}
}
}
function varPlus(e1) {
let _key1 = e1.key;
if(_key1 === "Enter") {
checker = new RegExp(_in.value.replace(/\s/g, "_"), "gi");
for(var i = 0; i < varArray.length; i++) {
if(checker.test(varArray[i])) {
window[varArray[i]] += 1;
console.log("var: " + varArray[i] + "\nvalue: " + window[varArray[i]]);
}
}
delete window["checker"];
}
}
_in.addEventListener('keydown', varCreate);
_in.addEventListener('keydown', varPlus);
<input id='in' type='text' />
The end result when attempting to utilize varPlus is that it'll console log all variable names and values which somehow increment in value when it should only be console logging only the variable name which I'm trying to access via user input followed by its value. I would greatly appreciate it if anyone can shed some light on how I'm encountering these errors.

First of all it is really helpful if you try and make your code executable :)
Now for the user generated variables you could do something like this:
// DOM Elements
const input_variable = document.getElementById("input_variable");
const button_createVariable = document.getElementById("button_createVariable");
// Variables
let userVariables = {};
// Event listeners
window.addEventListener("keyup", event => {if(event.key == "Enter") parseVariable()});
button_createVariable.addEventListener("click", parseVariable);
function parseVariable() {
// Get the variable name and remove all spaces
let variableName = input_variable.value.substring(0, input_variable.value.indexOf("=")).replace(/\s+/g, '');
// Get the variable value and remove all spaces
let variableValue = input_variable.value.substring(input_variable.value.indexOf("=") + 1, input_variable.value.length).replace(/\s+/g, '');
// Add the variable to the object
userVariables[variableName] = variableValue;
// Clear the input
input_variable.value = "";
// Log the object into the console
console.log(userVariables);
}
<input id='input_variable' type='text'/><button id="button_createVariable">Create</button>
WARNING You of course still need to verify the user input. At this state it will accept everything as input. But now you can loop through the object and count up (or whatever) if already exists.
Oh yes btw, the syntax is simply: <name> = <value> eg. foo = 10.. unimportant detail :P

JavaScript and Array's

EDIT I originally posted this with my version of the J.S but it's so far off no one can even help so i'm starting over. Here is the pseudocode i have done that needs to be translated into a Javascript program. Any help is appreciated!
I am a beginning programmer i understand this code will have multiple errors, that's why i am here. Array's and loops have given me much trouble while trying to learn them and especially with formatting them in JavaScript. The things i know are incorrect or still need i commented out i still need them, i also know i'm not passing anything i just can't seem to wrap my head around how to get them there. I'm also not sure if while gather input i'm using alter and prompt correctly. In the display function the spacing is necessary for when it will be displayed. Corrections and explanations are greatly appreciated.
Module main()
//Declare local variables
Declare endProgram = “no”
While endProgram == “no”
Declare Real notGreenCost[12]
Declare Real goneGreenCost[12]
Declare Real savings[12]
Declare String months[12] = “January”, “February”, “March”, “April”, “May”, “June”, “July”, “August”, “September”, “October”, “November”, “December”
//function calls
getNotGreen(notGreenCost, months)
getGoneGreen(goneGreenCost, months)
energySaved(notGreenCost, goneGreenCosts, savings)
displayInfo(notGreenCost, goneGreenCosts, savings, months)
Display “Do you want to end the program? Yes or no”
Input endProgram
End While
End Module
Module getNotGreen(Real notGreenCost[], String months[])
Set counter = 0
While counter < 12
Display “Enter NOT GREEN energy costs for”, months[counter]
Input notGreenCosts[counter]
Set counter = counter + 1
End While
End Module
Module getGoneGreen(Real goneGreenCost[], String months[])
Set counter = 0
While counter < 12
Display “Enter GONE GREEN energy costs for”, months[counter]
Input goneGreenCosts[counter]
Set counter = counter + 1
End While
End Module
Module energySaved(Real notGreenCost[], Real goneGreenCost[], Real savings[])
Set counter = 0
While counter < 12
Set savings[counter] = notGreenCost[counter] – goneGreenCost[counter]
Set counter = counter + 1
End While
End Module
Module displayInfo(Real notGreenCost[], Real goneGreenCost[], Real savings[], String months[])
Set counter = 0
While counter < 12
Display “Information for”, months[counter]
Display “Savings $”, savings[counter]
Display “Not Green Costs $”, notGreenCost[counter]
Display “Gone Green Costs $”, goneGreenCost[counter]
End While
End Module

A few notes:
Currently the program creates a few variables and functions that
don't seem to interact
Most of the edits below are not optimal - there are parts that
could be done by much simpler means (i.e. counter++) - But thats
for you to learn =P
I made quite a few assumptions of what you wanted the program to
do, they might be wrong, they might be right
var notGreenCost = []; //Array lengths don't need to be specified
var goneGreenCost = [];
var savings = [];
var months = ["January", "Feburary", "March", "April", "May", "June"];
//A boolean value (true | false) would suit this better as opposed to "yes"/ "no"
var endProgram = false;
var option = 0;
/* You dont need main functions in javascript
* migrated everything to be global :/
* Delete:
function main(){
// Move this (made it global): var endProgram = "no";
}
*/
// I don't think this is meant to be initMonths..
// Maybe something like getOptions?
function /*initMonths*/getOptions(){
while (endProgram == false){ //lowercase while
//Because prompt would block everything else until it gets input
//we probably want to move the prompt to be after the alerts
alert("options:"); //Clarity
alert("1 to enter data");
alert("2 to display data");
alert("3 to write data to a file");
alert("4 to read data from a file");
//Alter global "option" to take the value of the prompt
option = prompt("What would you like to do? Type:");
//} //I assume you want the rest of the code in this while loop - otherwise it will loop forever
// Delete this bracket (its unmatched): {
// Delete return statement as it will stop the function return option;
// Delete this bracket (its unmatched): }
//Create a variable to take the value of prompt (this should be outside the while loop) but it seem clearer for explanation purposes to be here
var toEnd;
toEnd = prompt("Do you want to end the program (enter yes or no)");
// Javascript uses != for "not equal to" and && for "AND"
while (toEnd != "no" && toEnd != "yes") {
toEnd = prompt("Please enter a value of yes or no");
}
//I think you want to assign the value of toEnd to endProgram
// Note the the below is not the only/best way to do it
if(toEnd == "no") {
endProgram = false;
} else if(toEnd == "yes") {
endProgram = true;
}
// While use brackets not End s
// End While
// End While
}//End while loop here
}
Javascript in a browser cannot alter files - writeToFile, readFromFile have all been removed
I believe you want months to be global, if it is then initMonths is unnecessary
getNotGreen:
function getNotGreen(){
//You don't need to specify types in Javascript
/*Integer*/ var counter = 0
while (counter < 6){ //lowercase while
//I'm assuming you want to combine the values of "Enter NOT GREEN energy costs for" and months[counter] - This is done by using the + sign
//Im also assuming you want to read the value into notGreenCost
//.push adds a value to a array
notGreenCost.push(prompt("Enter NOT GREEN energy costs for" + months[counter]))
//Returning here makes the rest of the function redundant
//}
//return notGreenCost[counter];
//}
//Javascript does not use Set
// Note that below is not the only/best way to do it
/*Set*/ counter = counter + 1
} //End the while loop here
}
getGoneGreen:
function getGoneGreen(){
//Counter should probably be local (not global) - use var
var counter = 0;
while (counter < 6){//lowercase while
//I'm assuming you want to combine the values of "Enter NOT GREEN energy costs for" and months[counter] - This is done by using the + sign
//Im also assuming you want to read the value into notGreenCost
//.push adds a value to a array
goneGreenCost.push(prompt("Enter GONE GREEN energy costs for" + months[counter]));
//See above (getNotGreen)
//}
//return goneGreenCost[counter];
/*Set*/ counter = counter + 1;
}//End while loop here
}
energySaved:
function energySaved(){
//Counter should probably be local (not global) - use var
var counter = 0;
while (counter < 6){//lowercase while
savings[counter] = notGreenCost[counter] - goneGreenCost[counter]
counter = counter + 1;
}
} //I assume you want to end energySaved here?
displayInfo:
function displayInfo(){
//Alert produced individual boxes, i assume you want the following in a single window?
// "\n" is a line break
alert("SAVINGS NOT GREEN GONE GREEN MONTH\n"+
"_________________________________________________\n");
//Counter should probably be local (not global) - use var
var counter = 0;
while (counter < 6){//lowercase while
alert( "$" + savings[counter] + "$" + notGreenCost[counter] + "$" + goneGreenCost[counter] + "" + months[counter]);
counter = counter + 1;
}
} //I assume you want to end displayInfo here?

innerHTML not working inside event handler function (Javascript)

I have created a function, updatePrice, which I have tied to the "click" event on the checkbox and radio buttons in my HTML form. Each checkbox and radio basically represents an item, with it's price as the value property of these <input> elements. When I check or uncheck any box, the function fires, loops through all elements in the form, and updates the total price of all the checked items into a div element I have below my form, with the id tag "priceOutput".
The following code works perfectly, printing out: The price of this item is $(price of item).
function updatePrice() {
var price = 0
for (i=0;i<=form.length;i++) {
var element = form[i]
if(element.checked) {
price+=parseInt(element.value)
}
document.getElementById("priceOutput").innerHTML = "The price of this item is $" + price + "."
}
}
But, if I switch the the last line around, the line is not printed at all:
function updatePrice() {
var price = 0
for (i=0;i<=form.length;i++) {
var element = form[i]
if(element.checked) {
price+=parseInt(element.value)
}
}
document.getElementById("priceOutput").innerHTML = "The price of this item is $" + price + "."
}
Why must I write the line in the {} of the for in order to work. Doesn't the price variable's scope extend over the entire updatePrice function?
I'm still rather new to programming, so do forgive me if this is an elementary question.

It seems to me that it isn't printing because you are causing an error. Since array indexing starts at 0 your for loop should not use <= but rather < :
for (i=0;i<form.length;i++) {
...
}
The reason why nothing gets printed then is because on the last loop the function errors and you setting the inner HTML never gets executed.

Seems like there is an error with your code, how about adding var to your for loop and removing the = from i<=form.length
for (var i = 0; i < form.length; i++)

JavaScript using isNaN to validate returns NaN

I have some code here that will make validations of whether or not the input from a text box is NOT an empty string and isNaN. When i do these validations on amounts entered, i would like it to add them up.. however when a user does not enter anything in one or more amount fields the program should just add entered fields. But instead i get NaN showing in the total field.
link to full code: http://jsfiddle.net/KxNqQ/
var $ = function (id) {
return document.getElementById(id);
}
var calculateBills = function () {
var myErrorFlag = "N";
for (i = 1; i <= 4; i++) {
AmountNumber = 'amount' + i;
AmountValue = $(AmountNumber).value;
if (AmountValue != "" && isNaN(AmountValue)) {
$(AmountNumber).style.color = "red";
myErrorFlag = "Y";
} else {
$(AmountNumber).style.color = "black";
myErrorFlag = "N";
}
}
if (myErrorFlag != "Y") {
var Amount = 0;
for (i = 1; i <= 4; i++) {
Amount += parseInt($('amount' + i).value,10);
}
$('total').value = Amount;
}
}
var clearFields = function () {
for (i = 1; i <= 4; i++) {
itemName = 'item' + i;
$(itemName).value = "";
}
for (i = 1; i <= 4; i++) {
amountName = 'amount' + i;
$(amountName).value = "";
}
$('total').value = "";
}
window.onload = function () {
$("clearfields").onclick = clearFields;
$("addbills").onclick = calculateBills;
}

I think you've got your requirements a little bit confused, or at the very least I was confused by them. So in order to answer your question, I'm going to rephrase the requirements so I understand them better. This is a useful exercise that I try to do when I'm not 100% sure of the requirements; if I can't get the requirements right, what's to say I'll get the code right?
So the requirements – as I understand them – are:
Given each amount input
When the input has a value
And that value is a number
Then add the value to the total
And make the input color black
But if the input does not have a value
Or that value is not a number
Then make the input color red
Going through your code, I can see a number of problems with it. First, I noticed that both AmountNumber and AmountValue are global variables, because they were not declared local with the var keyword. So before fixing our code, let's change that. Let's also change the variable names to something that more accurately describe what they are, hopefully making the code easier to understand:
var input = $('amount' + i);
var value = input.value;
Now, note that I chose to store the element in the input variable. This is so we don't have to look it up multiple times within the loop. Looking things up in the DOM can be expensive so we'll want to keep it to a minimum. There are other was to look up elements as well, such as getElementsByClassName, querySelector and querySelectorAll; those are left as an exercise for the reader to research and evaluate.
Next, in each iteration of the loop, you check that AmountValue is not a string and simultaneously is not a number:
if (AmountValue != "" && isNaN(AmountValue)) {
This will be true so long as AmountValue is truthy (which is the case for non-empty strings) and so long as isNaN thinks it's a number (which is the case for strings that contain numbers.) It really is rather confusing; if I understand your code correctly this clause is there to check for invalid input and if it is true should mark the input field red and set a flag. I.e. this is the but clause in the aforementioned requirements.
Let's rewrite this to be the when clause instead, we'll take care of the but later. Before we do that, let's look at the myErrorFlag. It's used – I think – to see whether all input is well formed and in that case, add it all up. Well, validation and summation can be done in one fell swoop, so let's get rid of the flag and sum the values while validating them. So we replace myErrorFlag with a total variable:
var total = 0;
Now, let's get back to our clause. The requirements say:
When the input has a value
And that value is a number
Then add the value to the total
In code, that should look something like this:
if (value && !isNaN(value)) {
total += parseInt(value, 10);
input.style.color = 'black';
}
There are a couple of things going on here. For one, the if statement has been turned on its head a bit from what it was. It first checks to see that value is truthy, then that it is a number. The second check can be a bit tricky to read, because it is essentially a double negation; in english it reads "is not not a number", i.e. "is a number". I'll leave it as an exercise for the reader to figure out whether there's a more easily understood way of writing this check.
Now what about the but clause in our requirements?
But if the input does not have a value
Or that value is not a number
Then make the input color red
Well, it's essentially the inverse of our previous statement, so let's simply add an else clause:
else {
input.style.color = 'red';
}
Because the requirements doesn't mention the total variable in this clause, it is simply ignored and doesn't show up in the end result.
Adding it all up (no pun intended) the code – with comments – looks like this:
var calculateBills = function () {
var total = 0;
for (i = 1; i <= 4; i++) {
// Given each amount input
var input = $('amount' + i);
var value = input.value;
if (value && !isNaN(value)) {
// When the input has a value
// And that value is a number
// Then add the value to the total
total += parseInt(value, 10);
// And make the input color black
input.style.color = 'black';
} else {
// But if the input does not have a value
// Or that value is not a number
// Then make the input color red
input.style.color = 'red';
}
}
$('total').value = total;
};
There are more things that could be learned from this to make for better code. For instance, this code will break if the number of inputs change, or if their id names change. This is because they are selected specifically by their IDs and as such, if those change then this code will no longer function.
Another potential issue is that we're setting inline styles on the inputs as we loop over them. This means that in order to keep this code up to date with the styling of the site, it'll have to change. Generally, mixing styling and functionality like this is not a good idea and should be avoided. One way of doing so is to use class names instead, and toggle these on and off. Incidentally, this could also help the previous problem I mentioned.
There are other problems as well, but we'll leave those for another day. Hope this helps!

Try this
var calculateBills = function () {
var Amount = 0;
for (i = 1; i <= 4; i++) {
var AmountElement = $('amount' + i),
AmountValue = AmountElement.value;
if (AmountValue != "" && !isNaN(AmountValue)) {
AmountElement.style.color = "red";
Amount += parseInt(AmountValue,10);
} else {
AmountElement.style.color = "";
}
}
$('total').value = Amount;
};
Demo
Anyway, instead of using elements with id like id="amount1", id="amount2", id="amount3", etc., you could use classes (e.g class="amount") and get them with .getElementsByClassName