I'm creating a node manually using vanilla JS. The idea is this alert appears after an input field if the maxlength limit has been reached and is removed if it returns below. This is being used on a CMS that users can use to create forms dynamically, so I won't know if the field will have a maxlength or not, or if it will have anything else after it. I'm using the following code:
document.querySelectorAll('input, textarea').forEach(element => {
if (element.hasAttribute('maxlength')) {
let maxChars = element.getAttribute('maxlength');
let elID = element.getAttribute('id');
let charWarning = document.querySelectorAll('#' + elID + ' + .char-limit');
element.addEventListener('input', () => {
let inputLength = element.value.length;
console.log(inputLength);
if (inputLength >= maxChars) {
if (charWarning.length == 0) {
let divAlert = document.createElement('div');
let divAlertText = document.createTextNode(maxChars + ' character limit reached on input');
divAlert.classList.add('text-danger', 'char-limit');
divAlert.setAttribute('aria-live', 'polite');
divAlert.setAttribute('aria-labelledby', elID);
divAlert.appendChild(divAlertText);
element.insertAdjacentElement('afterend', divAlert);
charWarning = document.querySelectorAll('#' + elID + ' + .char-limit');
}
} else {
// console.log(charWarning.length);
if (charWarning.length > 0) {
charWarning.remove(); // This is not working and I have no idea why.
}
}
});
}
});
For whatever reason, the .remove() function isn't working. It's throwing an error:
charWarning.remove is not a function at HTMLTextAreaElement
I don't really understand this. I thought it might be down to the fact that the initial setting of the charWarning prior to the listener was static, so I've added it again at the end of the function creating the warning element. It all works fine, but it's not removing the warning when below the maxlength and throwing that error.
For info, the commented out console.log:
// console.log(charWarning.length);
When uncommented does return 1, when the node has been added.
Can anyone point to what I'm doing wrong?
Ok, so after 2 days of no real responses, I took a late night stab at this again and somehow figured it out through trial and error. I thought the issue was to do with scoping but I couldn't figure out WHAT scope. In the end, I tried changing the "let" to "var" on the warning and that didn't work. So then I changed the selector from document.querySelectorAll to document.querySelector, cleaned up a little of the code and removed the else by using conditional chaining and voilà... result! Much cleaner, much better (and most importantly) functioning code...
However, on researching the properties of aria-live="polite" I discovered that creating and removing the node is the incorrect process. I can create it but when I want to update it for assistive technologies, it's the content I need to change. This kinda goes back to #ZainWilson-WCHStudent's first comment about showing and hiding the content. While I'm still not doing this as I believe it is incorrect for accessibility, it does kind of lean on that idea. I believe that this solution is much more elegant, efficient and (most importantly) accessible:
document.querySelectorAll("input, textarea").forEach((e) => {
if (e.hasAttribute("maxlength")) {
let maxChars = e.getAttribute("maxlength");
let elID = e.getAttribute("id");
let divAlert = document.createElement("div");
let divAlertText = document.createTextNode(
maxChars + " character limit reached on input"
);
divAlert.classList.add("text-danger", "char-limit");
divAlert.setAttribute("aria-live", "polite");
e.insertAdjacentElement("afterend", divAlert);
e.addEventListener("input", () => {
let charWarning = document.querySelector("#" + elID + " + .char-limit");
let inputLength = e.value.length;
if (inputLength >= maxChars) {
charWarning.appendChild(divAlertText);
} else {
if(charWarning.firstChild) {
charWarning.removeChild(charWarning.firstChild);
}
}
});
}
});
Here's a Codepen to test: https://codepen.io/tadywankenobi/pen/OJQXwwR
Related
(Using Javascript)
If I enter text in the textbox or not, the alert will not come up.
I know this is a simple fix but I can not figure it out!
(This is for learning purposes.)
Workout Log Test
<script type="text/javascript">
function myResults() {
myExercise();
myWeight();
mySets();
myReps();
myFunction();
}
function myExercise() {
var txtExercise = document.getElementById("txtExercise");
var txtOutput = document.getElementById("txtOutput1");
var name = txtExercise.value;
txtOutput1.value = "You destroyed, " + name + "!"
if (txtExercise.length === 0) {
alert ('Do you even lift?');
return;
First off, you're checking the "length" property of the element rather than the value of the input.
Second of all, you're checking against an integer value. If you were to simply read the value of the element, you're going to get text.
I'm guessing, what you want is something like:
var exercise = parseInt(txtExercise.value, 10);
if(exercise === 0) {
alert('Do you even lift?');
return;
}
But that's assuming txtExercise is an input element. Without seeing your markup, it's hard to be sure that any given answer will work.
Here you go, all fixed. You need an event handler, and this is a better if/else use case.
http://codepen.io/davidwickman/pen/vOKjqV
// Check the .value.length instead of just the .length
if (txtExercise.value.length === 0) {
alert('Bro, do you even lift?');
} else {
txtOutput1.value = "You destroyed, " + name + "!";
}
Assuming you have closed the function and if statement properly, you are missing a semi colon just before the if statement.
txtOutput1.value = "You destroyed, " + name + "!"; <---- here
What I'm building is a game where the computer generates a random number (1-100) and the user must guess the correct number. The goal is for the computer to compare the current guess to the previous guess and spit out a statement: "hot", "cold", "hotter", "colder", etc.
My Code (focus on the JS): CodePen fiddle
//global variables--computer generated guess, and guess log
var answer = Math.floor((Math.random() * 100)+1);
var guessArray = [];
var index = 0;
//user clicks submit button and guess is registered by computer
$("#submit").click( function(){
var guess = $("#guess").val();
guessArray.push(guess);
//prints out the answer and user guesses
$("#answer").text("Answer:" + " "+ answer);
$("#guessArrayPrint").text("You guessed: " + " " + guessArray + " ");
if (answer === guess) {
$("#statement").text("woo hoo right answer");
} else {
var currentDifference = Math.abs(answer-guess);
var currentDiffArray = [];
currentDiffArray.push(currentDifference);
if (index = 0) {
//if-else statement comparing current guess range to answer
if ( currentDifference >=1 && currentDifference <= 10){
$("#statement").text("Ouch! You're hot!");
} else {
$("#statement").text("Brr! You're cold!");
}
} else {
//if-else statement comparing current guess to previous guess
var previousDiff = answer- prevguess;
var prevguess = guessArray [i-1];
if( previousDiff < currentDifference){
$("#statement").text("Ahh! Getting Warmer!");
} else {
$("#statement").text("Brrr...getting colder");
}
}
index++
}
});
My nested if-else statements are not working. When a user inputs a guess, no matter how close to the answer, it always returns the statement "brr.. getting colder", which is in the "else" section.
Ideally when the user inputs their first guess if (index = 0) should run then when the second guess is input, it should move to the "else" statement with the previous guess variables. I tried moving around the variables, changed orders of if/else, and thought maybe it's the placement of index++. Nothing is working. Not sure if something is wrong with my variables , arrays, or the syntax of my if/else statements.
tl;dr: when the program is run only the "else" portion of the nested if-else statement is run. Not sure how to fix… I've gone through my code a number of times. The syntax, the arrays, and variables. Uncertain what's wrong.
You JS has if (index = 0). This should be if (index === 0).
Additionally, you need to cast the value of your input field to a number. You can do this using:
var guess = +$("#guess").val(); // + cast as a number
More syntax errors:
prevguess = guessArray[i - 1] --> prevguess = guessArray[index - 1];
Here is a partial working Fiddle. I ran through some scenarios, and the fiddle really only works if you give the application the right answer. The code has many syntax errors, bad refs and calculations. I would suggest opening the console or a debugger, identifying those issue, and fixing them.
Here is a Fully Functional Demo.
I am having a strange issue, but it is not surprising as I am a bit of a JavaScript newbie. Basically I am creating a simple high-low card game. (Draw two cards, highest card wins). Anyways, the code is below.
The basic flow of the program is pretty simple. I choose 2 random numbers (1-52). These numbers are mapped to a corresponding card. (i.e. number 1 is the ace of spades, number 37 is the jack of clubs, etc.). Anyways, after drawing the cards, the program is to display the corresponding card and determine the winner. At the end of all of this, i have an alert that comes up and and tells the winner of the draw and asks if the user wants to play again.
The problem I am having is this: Even though the program should have already displayed the image of the card and output the results to a text area, the alert box shows up before any of that actually occurs and never displays the cards or the results. Any ideas? I am posting all of the code so far and any help would be appreciated. Thanks in advance.
function drawCards() {
var oppCard = randNumber();
var customerCard = randNumber();
while (oppCard == customerCard) {
customerCard = randNumber();
}
var oppCardName = displayCard(oppCard, "oppImage");
var customerCardName = displayCard(customerCard, "custImage");
var result2 = "Your card was: " + customerCardName;
var result1 = "The opponent's card was: " + oppCardName;
var result3 = determineWinner(oppCard, customerCard);
var result4 = result3 + '\n' + result1 + '\n' + result2;
$("#textareaRes").text(result4);
playAgain(result3);
}
function determineWinner(oppsCard, customersCard) {
var oppValue = oppsCard % 13;
var customerValue = oppsCard % 13;
var winnerString = "";
if (oppValue == 0) {
oppValue = 13;
}
if (customerValue == 0) {
customerValue = 13;
}
if (oppValue == customerValue) {
winnerString = "You Tied.";
}
else if (oppValue > customerValue) {
winnerString = "You Lose.";
}
else if (oppValue < customerValue) {
winnerString = "You Win!!";
}
return winnerString;
}
function randNumber() {
var min = 1;
var max = 52;
var random = Math.floor(Math.random() * (max - min + 1)) + min;
return random;
}
function playAgain(resultString) {
if (resultString == "You Lose." || resultString == "You Win!!") {
alert(resultString);
var conf = confirm("Play Again?");
if (conf == true) {
$("#textareaRes").text("");
document.getElementById("custImage").src="./cardImages/default.png";
document.getElementById("oppImage").src="./cardImages/default.png";
}
else {
window.location = "#mainMenuPage";
}
}
else {
alert(resultString);
alert("Try Again.");
$("#textareaRes").text("");
document.getElementById("custImage").src="./cardImages/default.png";
document.getElementById("oppImage").src="./cardImages/default.png";
}
}
So I did not place the code in here for the display card function, just because for testing it is exceptionally long. It is just a giant switch case for all 52 random numbers. The finished product will actually be pulling from an XML file, but I used this just for testing purposes. (If, for some reason, you need to see the display cards function, let me know and I can post it.) Anyway, to recap, the last call made in the drawCards() function is the playAgain function. Upon running this code the results nor the card images are displayed. It just jumps straight to the alert that is called for by the playAgain function. This is probably a pretty noobish question, but I am a little perplexed by it. So any help you guys can offer would be GREATLY appreciated. Thanks.
EDIT: It actually performs correctly in a computer's browser. However, the problem happens on a mobile device like a phone or tablet. So this is probably something that I am doing incorrectly here. Any help is greatly appreciated.
Changes in the browser doesn't show up as long as your Javascript code is running.
The browser is event driven, so changing an element in the DOM doesn't show the change immediately, instead an event is triggered to redraw the element. When your function has finished running, the browser will handle any pending events and show the changes.
So, when building an application, you have to use the same approach so that the browser has a chance to show the changes.
For anyone who finds this looking for the solution to the problem, the solution can be found in this answer: https://stackoverflow.com/a/13338585/870729
Here is a working fiddle of a simple example:
jQuery(function($) {
$.when($('#empty-me').html('')).done(function() {
alert('I did it!');
});
});
"./cardImages/default.png"
im not sure ... but try "../cardImages/default.png" ... i always use 2 dots for come to a higher level
I have web page with some really large tables that I'm filtering using some jquery routines I wrote. Anyway, when these tables get really large and the filtering functions can take some time to complete. So I figured I'd unhide a animated gif so the user had some feedback. However, the gif never appears when I call:
$('#loadingimg').show();
Unless I put an alert statement in front of it. I apologize for the ugly code, I'm not an experienced jquery/javascript programmer.
function filter()
{
var eles = ["mtmprogram","rate","stage"];
var tag;
var classes='';
$('#loadingimg').show();
//alert('hi');
$('.report').hide();
for (var i in eles)
{
tag = '#' + eles[i] + ' option:selected';
if ($(tag).val())
{
//$('.'+ $(tag).val()).show();
classes = classes + '.' + $(tag).val();
}
}
if (classes == '')
$('tr.report').show();
else
$(classes).show();
filterSubtables('Loan Number');
$('#loadingimg').hide();
}
Many thanks!
Maybe you aren't giving the #loadingimg element enough time to display. You could test this by running the rest of your code in a timeout:
function filter()
{
var eles = ["mtmprogram","rate","stage"],
classes = '';
$('#loadingimg').show();
//alert('hi');
setTimeout(function () {
$('.report').hide();
for (var i = 0, len = eles.length; i < len; i++)
{
var $tag = $('#' + eles[i] + ' option:selected');
if ($tag.val())
{
//$('.'+ $tag.val()).show();
classes = classes + '.' + $tag.val();
}
}
if (classes == '')
$('.report').show();
else
$(classes).show();
filterSubtables('Loan Number');
$('#loadingimg').hide();
}, 500);
}
Notice that I changed how the tag variable is used (this creates less CPU overhead to make less jQuery selections and to use as local a variable as possible). I also changed your loop to a better format that performs amazingly faster than for ( a in b ): http://jsperf.com/jquery-each-vs-for-loops/2
NOTE: Originally had this listed as a memory leak. After looking into this deeper, I discovered that it's not a memory issue. It's just a very slow script. Any suggestions to speed this up would be greatly appreciated.
ANOTHER NOTE: After looking into this even further, I see that FF does not support any type of CSS that formats text in overflow. There is a hack and a workaround for that hack...but that will not be a suitable solution.
I have voted for and joined the e-mail list on this particular bug at mozilla. It's almost six years old so I resolve that users will just have to deal with it for now. At least it's not a common scenario for our product.
Original post:
The script truncates the value of an element and appends '...' while its scrollWidth is greater than it's offsetWidth. (e.g. A value of "LastName, VeryLongFirstName"will change to something like "LastName, Ver...", depending on the width of the column)
var eTable = document.getElementById(this._eDiv.id + "_tbl");
//...lots of code here...
//function called that gets all cells in a table, loops through them and clips the text
addEventListenerEx(window, "load", function() {
var aCells = eTable.getElementsByTagName("DIV");
window.alert(aCells.length);
//When aCells is length of 100, we're ok...but when it's big (like 3,000) I have problems
for (var i = 0; i < aCells.length; i++){
Grid.clipText(aCells[i]);
}
}, false);
//...lots of code here...
//This is the function doing the actual clipping
Grid.clipText = function (oDiv) {
//for tooltip
var oCurDiv;
var oTagA;
var sToolTip;
if (oDiv.firstChild) {
if (oDiv.firstChild.firstChild){
oCurDiv = oDiv.firstChild;
while (oCurDiv) {
if (is.ie) {
oTagA = oCurDiv;
} else {
// there are some different between IE & FireFox.
oTagA = oCurDiv.firstChild.parentNode;
}
if (oTagA.tagName == "A") {
sToolTip = oTagA.innerHTML;
if (sToolTip.indexOf('<b>') > 0) {
sToolTip = sToolTip.replace('<b>',"");
sToolTip = sToolTip.replace('</b>',"");
}
if (sToolTip.indexOf('<B>') > 0) {
sToolTip = sToolTip.replace('<B>',"");
sToolTip = sToolTip.replace('</B>',"");
}
oTagA.parentNode.title = convertHTMLToText(sToolTip);
}
oCurDiv = oCurDiv.nextSibling;
}
} else {
oDiv.title = convertHTMLToText(oDiv.innerHTML);
}
}
//NOTE: Additional steps to take for non-IE browsers
if (!is.ie) {
var oText = oDiv;
while (oText.nodeType != 3) {
oText = oText.firstChild;
}
var sDisplayText = oText.nodeValue;
if (sDisplayText.length < 3) return;
var lastThree;
sDisplayText = sDisplayText.slice(0, parseInt(oDiv.offsetWidth / 5));
oText.nodeValue = sDisplayText + "...";
//NOTE: Bad things happen here because of this loop
while (oDiv.scrollWidth > oDiv.offsetWidth && sDisplayText != "") {
lastThree = sDisplayText.slice(-3);
sDisplayText = sDisplayText.slice(0, sDisplayText.length - 3);
oText.nodeValue = sDisplayText + "...";
}
oText.nodeValue = sDisplayText + lastThree.slice(0, 1) + "...";
while (oDiv.scrollWidth > oDiv.offsetWidth && sDisplayText != "") {
oText.nodeValue = sDisplayText + "...";
}
}
The code works. However, the problem is that it's called over and over again after a table is loaded on the page. When the table is huge (>1,500 cells), that's when the issue starts.
So, I'm really looking for a way to make this sample (particularly the WHILE loop) more efficient.
Nothing in that is going to leak by itself. You're probably leaking oText in the closure, can you show the surrounding code?
Btw, here is a vastly more efficient way of doing this:
http://jsfiddle.net/cwolves/hZqyj/
If you really want to keep doing it the way you are, you can estimate the cutoff point by taking the length of the string and multiplying it by the proportional width it needs to be...
e.g. if the string is 100 characters and it's 2x as long as it should be, cut it to 50 chars and re-check. Or you could implement a binary 'search' algorithm to get the correct length.
The work-around, and best answer to my problem came from basic arithmetic: cross multiplication
I posted my answer in a more popular stackoverflow thread discussing the topic in better detail.