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Do While Loop Mixed With Function Loop

I am writing a simple program for school and running into trouble with an issue I am hoping someone could help me with
These are the assignment parameters:
Create a small JavaScript program that:
Creates a variable 'total' with a value of 0.
Use a do-while loop & function to prompt the user to enter a series of numbers, or the word "quit" - the quit command should be case insensitive.
If the user enters a number, add the new number to a running total.
If the user enters the word "quit" the loop should stop execution.
If the user enters a word other than quit the prompt message should change to let the user know they entered an invalid data type
When the loop is exited, display a message giving the total of the numbers entered
My code achieves all assignment parameters except I can't figure out how to get the prompt to disappear after the quit command is entered. The result still displays on the screen but the prompt keeps looping.
Here is my code:
var inputCounter = 0;
var total = 0;
newInput = null;
quit = /quit/i
function askForNum(a) {
do {
var newInput = prompt(a);
if (!newInput.match(quit)) {
if (newInput < "A" && newInput > "" ) {
var addThis = parseFloat(newInput);
}
if (isNaN(newInput)) {
askForNum("That wasn't a number! type \"quit\" to see the results!");
} else {
total += addThis;
inputCounter++;
askForNum("Every number you enter gets added together! type \"quit\" to see the results!");
}
}
} while (!newInput.match(quit)) {
document.getElementById("addition-script").innerHTML = "<b>TOTAL:</b> " + total + "<br><b># OF ENTRIES:</b> " + inputCounter;
return;
}
}
if (total == 0){
askForNum("initial: Every number you enter gets added together! type \"quit\" to see the results!");
}

You are calling the askForNum function from inside itself (recursion), in effect starting a new do-while loop inside the previous one every time you type anything other than "quit".

How to choose and work with a drop down list in js

I got this problem. I created a drop down list for choosing the algorithm to work with. It works with the first option but not all of them. Could you please help me?
Thanks in advance
var form1 = document.getElementById('form1');
var form2 = document.getElementById('form2');
var form3 = document.getElementById('form3');
var formArray = [];
formArray.push(form1.innerHTML);
formArray.push(form2.innerHTML);
formArray.push(form3.innerHTML);
//select drop down list//
function changeToCal() {
dropDownList.selectedIndex--;
document.getElementById('form').innerHTML = formArray[dropDownList.selectedIndex];
}
//Calculate //
document.getElementById('form').addEventListener("submit",
function(event) {
var fieldy = document.getElementById('fieldy');
var fieldx = document.getElementById('fieldx');
var resultField = document.getElementById('resultField');
var x = parseFloat(fieldx.value);
var y = parseFloat(fieldy.value);
if(!fieldy.value || !fieldx.value) {
alert("Please enter numbers in the fields!");
} else if (dropDownList.selectedIndex = 1) {
var result = (y / 100) * x;
resultField.innerText = "Answer: " + result + "."
event.preventDefault();
} else if (dropDownList.selectedIndex = 2) {
var result = (100 / y) * x;
resultField.innerText = "Answer: " + result + "."
event.preventDefault();
} else if (dropDownList.selectedIndex = 3) {
var result = (y / x) * 100;
resultField.innerText = "Answer: " + result + " %."
event.preventDefault();
} else {
resultField.innerText = "Error"
event.preventDefault();
}
}
);
https://codepen.io/anon/pen/VMZNwQ

This line:
} else if (dropDownList.selectedIndex = 1) {
needs to use a comparison equals operator rather than an assignment equals operator:
} else if (dropDownList.selectedIndex === 1) {
The other if/else clauses are similarly incorrect.
I highly recommend using a decent IDE, it would highlight potential mistakes like this for you.
You will also need to change this:
dropDownList.selectedIndex--;
document.getElementById('form').innerHTML = formArray[dropDownList.selectedIndex];
to this:
document.getElementById('form').innerHTML = formArray[dropDownList.selectedIndex - 1];
The selectedIndex is live, if you change it using -- that will cause the selected value to be updated.
The way the result is output assumes there is an <h3> with the id resultField but only one of your forms has that id set.
Other miscellaneous suggestions include...
The id attributes need to be unique throughout the document. You currently have 3 hidden forms and you copy around the HTML, leading to 4 elements with each id (resultField, fieldx, fieldy). Whether document.getElementById grabs the right one is down to luck.
Rather than copying around the innerHTML of those forms you'd be better off simply showing and hiding the existing forms using CSS. Alternatively you could use just 1 form and update the relevant text to match the current algorithm.
Listening for the submit event of the form seems odd. Why not use a regular button and listen for the click event?
If you do decide to keep the 3 forms I would suggest registering separate button handlers for each one. The fact that so much of your code is inside a big if/else is a sign that you actually need multiple functions rather than a single function that has to figure out which mode it is in. The code they share could be factored out if appropriate.

how to remove the last character of an input field using AngularJS

The title of this question is probably wrong, but i can't think of how to name it.
I'm trying to build a simple calculator using AngularJS. Right now its functioning, but i'm trying to add some other buttons. I want a "delete" key and a decimal key. The delete key is what i'm focused on now.
If someone clicks, 3, then 3 again. we have 33. (this calculator currently, can only accept a left and right operand, and an operator separating them (ex, 3+3, or 56*486, etc). not multiple operators or operands). Now say the user were to enter 334, but they want the 4 taken off because they meant to click 5. How do I use javascript to delete the most recent number if an operator or equals hasn't been pressed?
If i had to guess, it's going to be something like this:
$scope.deleteNumb = function(d){
if(!$scope.operator){
// if no operator, delete most recent left operand
}
else{ //delete most recent right operand}
}
};
The "C" button doesn't work. I had that set up as "Clear" which refreshed the page to start a new calculation. I need a way to figure out how to delete the existing answer without using location.reload();
So the main thing here, is trying to delete the recent most operand, whether it be left or right, depending if an operator has been clicked or not.
My code is here:
https://codepen.io/tevon/pen/Moewba

For clear (C) did you try to clear all values in setClear
$scope.setClear = function (a) {
$scope.leftOperand = "";
$scope.operator = "";
$scope.rightOperand = "";
$scope.answer = "";
};

to delete a part of your number; have a look to substr as your input is a string :
For exemple :
$scope.removeBtn = function(){
var tmp = $scope.leftOperand;
console.warn("test",tmp)
$scope.leftOperand = tmp.substr(0,tmp.length-1);
}
This function removes the last number of your leftOperand.
Adapt it to your need for left/right

$scope.setClear = function (a) {
// $scope.clear = location.reload();
var result = $scope.leftOperand + $scope.operator + $scope.rightOperand;
result = result.substring(0, result.length - 1);
if ($scope.operator){
$scope.rightOperand = result;
}
else {
$scope.leftOperand = result;
}
};
Not tested.. Would have to tweak a little when operators come i guess

Unable to Get Output From While Loop in Javascript

I'm working on my final project of the Winter 2017 quarter to demonstrate how to use Regular Expressions in both C# and JavaScript code behind pages. I've got the C# version of my demonstration program done, but the JavaScript version is making me pull what little hair I have left on my head out (no small achievement since I got a fresh buzz cut this morning!). The problem involves not getting any output after applying a Regular Expression in a While loop to get each instance of the expression and printing it out.
On my HTML page I have an input textarea, seven radio buttons, an output textarea, and two buttons underneath (one button is to move the output text to the input area to perform multiple iterations of applying expressions, and the other button to clear all textareas for starting from scratch). Each radio button links to a function that applies a regular expression to the text in the input area. Five of my seven functions work; the sixth is the one I can't figure out, and the seventh is essentially the same but with a slightly different RegEx pattern, so if I fix the sixth function, the seventh function will be a snap.
(I tried to insert/upload a JPG of the front end, but the photo upload doesn't seem to be working. Hopefully you get the drift of what I've set up.)
Here are my problem children from my JS code behind:
// RegEx_Demo_JS.js - code behind for RegEx_Demo_JS
var inputString; // Global variable for the input from the input text box.
var pattern; // Global variable for the regular expression.
var result; // Global variable for the result of applying the regular expression to the user input.
// Initializes a new instance of the StringBuilder class
// and appends the given value if supplied
function StringBuilder()
{
var strings = [];
this.append = function (string)
{
string = verify(string);
if (string.length > 0) strings[strings.length] = string;
}
this.appendLine = function (string)
{
string = verify(string);
if (this.isEmpty())
{
if (string.length > 0) strings[strings.length] = string;
else return;
}
else strings[strings.length] = string.length > 0 ? "\r\n" + string : "\r\n";
}
this.clear = function () { strings = []; };
this.isEmpty = function () { return strings.length == 0; };
this.toString = function () { return strings.join(""); };
var verify = function (string)
{
if (!defined(string)) return "";
if (getType(string) != getType(new String())) return String(string);
return string;
}
var defined = function (el)
{
// Changed per Ryan O'Hara's comment:
return el != null && typeof(el) != "undefined";
}
var getType = function (instance)
{
if (!defined(instance.constructor)) throw Error("Unexpected object type");
var type = String(instance.constructor).match(/function\s+(\w+)/);
return defined(type) ? type[1] : "undefined";
}
}
Within the code of the second radio button (which will be the seventh and last function to complete), I tested the ScriptBuilder with data in a local variable, and it ran successfully and produced output into the output textarea. But I get no output from this next function that invokes a While loop:
function RegEx_Match_TheOnly_AllInstances()
{
inputString = document.getElementById("txtUserInput").value;
pattern = /(\s+the\s+)/ig; // Using an Flag (/i) to select either lowercase or uppercase version. Finds first occurrence either as a standalone word or inside a word.
//result = pattern.exec(inputString); // Finds the first index location
var arrResult; // Array for the results of the search.
var sb = getStringBuilder(); // Variable to hold iterations of the result and the text
while ((arrResult = pattern.exec(inputString)) !==null)
{
sb.appendLine = "Match: " + arrResult[0] ;
}
document.getElementById("txtRegExOutput").value = sb.toString();
/* Original code from C# version:
// string pattern = #"\s+(?i)the\s+"; // Same as above, but using Option construct for case insensitive search.
string pattern = #"(^|\s+)(?i)the(\W|\s+)";
MatchCollection matches = Regex.Matches(userTextInput, pattern);
StringBuilder outputString = new StringBuilder();
foreach (Match match in matches)
{
string outputRegExs = "Match: " + "\"" + match.Value + "\"" + " at index [" + match.Index + ","
+ (match.Index + match.Length) + "]" + "\n";
outputString.Append(outputRegExs);
}
txtRegExOutput.Text = outputString.ToString();
*/
} // End RegEx_Match_The_AllInstances
I left the commented code in to show what I had used in the C# code behind version to illustrate what I'm trying to accomplish.
The test input/string I used for this function is:
Don’t go there. If you want to be the Man, you have to beat The Man.
That should return two hits. Ideally, I want it to show the word that it found and the index where it found the word, but at this point I'd be happy to just get some output showing every instance it found, and then build on that with the index and possibly the lastIndex.
So, is my problem in my While loop, the way I'm applying the StringBuilder, or a combination of the two? I know the StringBuilder code works, at least when not being used in a loop and using some test data from the site I found that code. And the code for simply finding the first instance of "the" as a standalone or inside another word does work and returns output, but that doesn't use a loop.
I've looked through Stack Overflow and several other JavaScript websites for inspiration, but nothing I've tried so far has worked. I appreciate any help anyone can provide! (If you need me to post any other code, please advise and I'll be happy to oblige.)

jquery: fix first misfire of if()

My js fiddle is here:http://jsfiddle.net/brvnhg1w/
(Please run the above fiddle first) If you double click the three dots it turns into a textbox, once you click out of press enter it goes back to being text. That works fine.
I want to do an update in the DB via an ajax call if the text has changed, but the first time you change the text (eg: from the three dots to, for example, "111") if you look in the console it says "unchanged" instead of "changed" and if you look at this line: console.log("Id: "+this.id+ " Value: " +this.value+ " OldValue:" +v ); thats gets printed in the console, for some reason it takes the new value and gets prints it as the prev value :(
So basically: if I have my ajax code in the "changed" part, the first time the client changes the textbox - it wont to fire... :(
The problem seems to be in this part of the code:
var n = prev.ix.indexOf(this.id);
var v=prev.val[n];
if(this.value!=v){
//value changed
console.log("changed");
prev.val[n]=this.value;//update existing value
// do .ajax - update the DB
}else{
console.log("unchanged");
}
console.log("Id: "+this.id+ " Value: " +this.value+ " OldValue:" +v );

The problem is when you check if the current input is in your array, you set the value. So once you hit the condition, the value will always be the same the first time.
To counter that, instead of pushing a value in the array, push an empty string '':
if($.inArray(this.id,prev.ix) == -1){
prev.ix.push(this.id);
prev.val.push('');
}
Fiddle : http://jsfiddle.net/brvnhg1w/5/

When the function first fires (and every subsuquent time) you are pushing the values into your arrays in prev. But that is the array the value is being compared against, so it compares the first value to itself and logs 'unchanged'. You might have to code an edge case for the initial run:
var n = prev.ix.indexOf(this.id);
var v=prev.val[n];
var flag = true;
if(this.value!=v || flag){
//value changed
console.log("changed");
prev.val[n]=this.value;//update existing value
// do .ajax - update the DB
//set flag to false, initial run over
flag = false;
}else{
console.log("unchanged");
}
console.log("Id: "+this.id+ " Value: " +this.value+ " OldValue:" +v );
http://jsfiddle.net/5eru6mt2/1/