|
JavaScript - Noob Help: General Problem
I've only just stated to teaching myself the general basics of web development, and I've hit a problem which I haven't been able to fix, even after some extensive research I haven't found a solution. The problem is not in the HTML I'm quite sure, hence why I deemed this to be the best place to post this. I'm sorry for wasting your time on something stupid like this, but I'm completely lost! Extra: I really couldn't think of a title that could describe this 'problem', my bad.
Description: When clicking the calculate button nothing happens, but when I changed the code inthere to something easy (just print a line in a HTML paragraph) it worked. So by that I was able to deduce the problem lies somewhere in the Javascript. Code: <!DOCTYPE html>
<html>
<body>
<div>
<form>
<fieldset>
<h1>Quadratic equation</h1>
a:<input type="text" id="a" name="a"><br><br>
b:<input type="text" id="b" name="b"><br><br>
c:<input type="text" id="c" name="c"><br><br>
<button type="button" onclick="vkv()">Calculate</button>
</fieldset><br>
<fieldset>
<p id="output">Answer appears here</p>
</fieldset>
</form>
</div>
<script>
function vkv() {
var a = document.getElementById(a);
var b = document.getElementById(b);
var c = document.getElementById(c);
var D = pow(b,2) - 4 * a * c;
if (D >= 0){
var x1 = (-b + sqrt(D)) / (2 * a);
var x2 = (-b - sqrt(D)) / (2 * a);
if (x1 == x2) {
document.getElementById("output").innerHTML = "Value for x is:" + x1 + ".";
} else {
document.getElementById("output").innerHTML = "Values for x a " + x1 + " en " + x2 + ".";
}
} else {
document.getElementById("output").innerHTML = "Discriminant is negative, " + D + ".";
}
}
</script>
</body>
</html>
Reply With Quote 02-03-2015, 10:31 PM #2 jmrker View Profile View Forum Posts Senior Coder Join Date Aug 2006 Location FL Posts 3,175 Thanks 39 Thanked 510 Times in 504 Posts Welcome to the forum... NOTE: I have not tested the logic of your code to see if it give the right answers, but this should get you started by at least seeing some results displayed. Primary problem was not using Math. before the math commands like pow and sqrt. Also, need quotes around id values in the document.getElementById statements And those statements require a value associated with the element Plus, it returns a string, hence the need for a Number() function or some other string to conversion. It is always a good idea to check the error console on most browsers to get an idea of the simple problems. That's where I found most of your errors. Code: <!DOCTYPE html>
<html>
<body>
<div>
<form>
<fieldset>
<h1>Quadratic equation</h1>
a:<input type="text" id="a"><br><br>
b:<input type="text" id="b"><br><br>
c:<input type="text" id="c"><br><br>
<button type="button" onclick="vkv()">Calculate</button>
</fieldset><br>
<fieldset>
<p id="output">Answer appears here</p>
</fieldset>
</form>
</div>
<script>
function vkv() {
var a = Number(document.getElementById('a').value);
var b = Number(document.getElementById('b').value);
var c = Number(document.getElementById('c').value);
var D = Math.pow(b,2) - 4 * a * c;
if (D >= 0){
var x1 = (-b + Math.sqrt(D)) / (2 * a);
var x2 = (-b - Math.sqrt(D)) / (2 * a);
if (x1 == x2) {
document.getElementById("output").innerHTML = "Value for x is:" + x1 + ".";
} else {
document.getElementById("output").innerHTML = "Values for x a " + x1 + " en " + x2 + ".";
}
} else {
document.getElementById("output").innerHTML = "Discriminant is negative, " + D + ".";
}
}
</script>
</body>
</html>
Good Luck! Similar TutorialsI'm having a problem. All i want to happen is this: The program asks you what's up. It gives you a prompt and the prompt message tells you to say "nm" (it means nothing much) And the if statement is that if you put nm into that prompt, it'll display a message. However, when i put in the prompt, even if i put in a bogus message, it'll still display the if statement. What do i do? Here's my code. Code: <html>
<head>
<title> The nothing much page! </title>
<script type="text/javascript">
var nmj;
alert("what's up man?");
var nmj = prompt("say nm , it means nothing much");
if (nmj = "nm")
{
alert("What!? Nothing much!? Sounds boring.")
}
alert(nmj);
</script>
</head>
<body>
NOTHING MUCH? WHATTT!?!?
</body>
</html>
I am trying to dynamically add rows to a table when the user clicks a button. here my function Code: function addFocusArea()
{
if(addTlFocusAreaCount <= 5)
{
//Create new Title row
var titleRow = document.createElement("tr");
var titleCol = document.createElement("th");
var titleText = document.createTextNode("Additional Focus Area " + addTlFocusAreaCount);
titleCol.appendChild(titleText);
titleRow.appendChild(titleCol);
document.getElementById("focusTable").appendChild(titleRow);
//Create new category row
var categoryRow = document.createElement("tr");
var categoryCol = document.createElement("td");
var categorySelect = document.createElement("select");
var categories = document.getElementById("<%=DecisionToolKeys.PRIMARY_FOCUS%>");
//copy a dropdown menu that is already existing on the page
for(var i=0; i<categories.length; i++)
{
var option = document.createElement("option");
option.value = categories[i].value;
option.text = categories[i].text;
categorySelect.options.add(option);
}
categoryCol.appendChild(categorySelect);
categoryRow.appendChild(categoryCol);
document.getElementById("focusTable").appendChild(categoryRow);
addTlFocusAreaCount++;
}
else
{
alert("You cannot add more than five additional practice areas.");
}
}
And here is my button Code: <input type="button" value="Add Focus Area" onclick="JavaScript:addFocusArea()"/> This is working in Firefox and Chrome, but not IE 8. Any clue as to why? Thanks, Nick Hi, I need help creating a function. It want it to: run when the page loads and every x seconds after. On loading I need it to connect to a db(preferably w ajax) and store results as variables I can reuse in other functions. And finally, after some math equations I can do, print the results on the page. I've been toying with this and I've realized its not as easy as I thought. Think I'm having problems with variable scope. Php is my main scripting language, of which I am fluent and have a working version of this. But I want it to run on the client side and relieve my server. Sorry if this is vague or incorrectly formatted, I'm on a phone browser. A guide or detailed demonstrations would be great, however pointing me in the right direction would me most apreciated. Hi, To put it bluntly I am a newbie to Javascript. I manage my own site using skills I have developed through learning code and need some help with debugging. My website is www.simplysafes.co.uk, in my IE it tells me I have an error with line 106 and char 2. Can anyone help me with this?? I would really appreciate it. Thanks in advance. James Hello; I'll begin like so many others before me, and apologize now if this post is in the wrong place, but since I don't exactly know what type of code I need, I'm not sure where to post this query. Let me preface this request by stating the obvious; I have almost no knowledge of coding. I've been watching tutorials for help with building a site for my small service-type business. I need coding that will allow my visitors to input their zip code to see if they reside in my service area. After they enter the zip and click the submit button, a page should pop up with one of two messages when they either are or are not in my service area. (I would undoubtedly need to list [somewhere in the coding] all the zip codes that are within my service area, and any zip codes not listed would bring up a message that the visitor is outside my service area.) I hope this makes sense, and someone can point me in the right direction. Thank you, in advance to any and all who respond, and keep in mind that you may have to dumb-down your responses for me to be able to understand. I create a cookie on my homepage that tracks a number, the next time they view, js calculates another number and subtracts the saved number. Is the cookie value created accessible from a page other than the home page? i.E. I want to create a popup window that shows the calculation but i can seem to pass the variable generated from my external js script to the internal script/page. Am i able to call the getCookie class i created from the internal script even if the class is held in the external script or is it only accessible from the page that created the cookie? If its a dumb question, sorry im relatively new. I have a general javascript question. It may apply in this forum but maybe in the asp forum. I have a java applet on a site that I am building. If someone visiting the site doesn't have their javascript turned on, and chooses not to, is there some line of code that I can use that will detect that and replace the applet for an image I create? The site is developed in asp, but being that it is a javascript question, I thought it may apply here. Gary hi, I would like your help on the following matter. I have a JavaScript file currently reading from another site xml file in (utf-8) and I would like to store those data in my database which is in SQL_Latin1_General_CP1_CI_AS. Is there any function in JavaScript that can encode (convert) text from utf-8 to SQL_Latin1_General_CP1_CI_AS or any other way to do that? Hi could someone please help?... I am a total beginner to javascript... but does anyone know of a code, including links to an image folder, for displaying 6 fullscreen images in random order without repeat for a given user? I've seen specific examples using shuffle on the site, but could anyone write a general code for any given images? Many thanks in advance Hi, as the title states, I'm trying to learn some basic javascript, more particularly, jQuery. I HATE having to "allow" active content to run on my IE browser. Is there a way to allow active content permanantly? Instead of having to click allow each time I refresh or reload my test pages? Also, IE keeps freezing or crashing when I run pages with scripts on them. Is this just my browser? or something to do with the active content permissions? Trying to google my questions, but no luck yet. Hello, I'm new to this forum. I want to improve my ability to write JavaScript and am looking for a friendly place to find some constructive criticism and suggestions on my code. This script does not have any practical use (that I can think of); it calculates prime numbers. It is just an exercise. I am looking for suggestions on all aspects from the CSS/aesthetics to the HTML and of course the JavaScript. I posted the script here. One definite thing that bugs me is the cursor is not in the text field when the page loads. Also it would be better if the user had the option of hitting the return key in addition to the submit button. Suggestions appreciated. Code: <!DOCTYPE html>
<html lang="en">
<head>
<title>Prime Number Calculator</title>
<style type="text/css">
form{
width: 200px;
border: solid 3px blue;
border-style: double;
padding:5px;
text-align:center;
background-color:#eee;
}
#title{
text-align:center;
border: solid 1px blue;
background-color:#fff;
margin:5px;
padding:0px;
}
</style>
<script src="jquery.js" type="text/javascript"></script>
<script type="text/javascript">
var candidates = new Array();
function calculatePrimes(form){
var max = form.input.value;
//Check to make sure input is a number
if(isNaN(max)){
alert("Dude, you must enter a number!");
}
for(i=2; i<=max; i++){candidates[i]=i;}
var i=2;
for(i=2; i<Math.sqrt(max); i++){
if (candidates[i]!=0){
var j=i*i;
while(j<max){
candidates[j] = 0;
j=j+i;
}
}
}
//Pull the primes out of the candidates
i=2;
var primesOut = "";
for(i=2; i<max; i++){
if(candidates[i]!= 0){
primesOut = primesOut + ((i>2)?", " : "" ) + candidates[i];
}
}
form.output.value = primesOut;
}
</script>
<head>
<body>
<form>
<h2 id="title">Prime-Number Calculator</h1>
Check up to:<input type="text" name="input" size="5" value="100" \> <br />
<textarea rows="5" cols="20" name="output"></textarea>
<input name="calc" value="Find!" type=button onClick="calculatePrimes(this.form)">
</form>
</body>
</html>
please could you help me i am using highcharts and cant get the dates to show at the bottom from mysql over 5 days please could some one help me with this thank you here is the chart database layout code Code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Daily Temperature 8 Conv</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>
<script src="./js/highcharts.js" type="text/javascript"></script>
<script type="text/javascript" src="js/theme-wsl.js"></script>
</head>
<div id="container" style="width: 800px; height: 400px; margin: 0 auto"></div>
<?php
$db = @mysql_connect("localhost", "8conv", "*******") or die("Connection Error: " . mysql_error());
mysql_select_db("tempmonitor") or die("Error connecting to db.");
$sql = "SELECT * FROM `8conv`";
$result = mysql_query($sql);
$data = array();
while ($row = mysql_fetch_array($result)) {
$temp1[] = (int)$row['temp1'];
$temp2[] = (int)$row['temp2'];
$time[] = $row['timestamp'];
}
$temp1 = json_encode($temp1);
$temp2 = json_encode($temp2);
$time = json_encode($time);
?>
<script type="text/javascript">
var chart = new Highcharts.Chart({
chart: {
renderTo: 'container'
},
title: {
text: 'Weekly Temperature',
x: -20 //center
},
subtitle: {
text: 'Source: 8 conveyor',
x: -20
},
tooltip: {
formatter: function() {
return '<b>'+ this.series.name +'</b><br/>'+
this.x +': '+ this.y +' oC ';
}
},
xAxis: {
type: 'datetime',
tickPixelInterval: 150,
maxZoom: 20 * 1000
},
yAxis: {
title: {
text: 'Temperature ( oC )'
},
plotLines: [{
value: 0,
width: 1,
color: '#808080'
}]
},
series: [{
name: 'Temp 1',
data:<?php echo $temp1; ?>,
},
{
name: 'Temp 2',
data:<?php echo $temp2; ?>,
}]
});
</script>
</head>
</body>
</html>
thanks i got this code which will open a new link in a new window. Code: <script type="text/javascript">
$(function(){
$(".popup").click(function(event){
event.preventDefault();
var href = $(this.)attr("href");
var width = $(this.)attr("data-width");
var height = $(this.)attr("data-height");
var popup = window.open (href, "popup",
"height=" + height +",width=" + width + "");
});
});
</script>
This is the html which it should be targeting. Code: <li><a href="http://www.google.com" data-width="600" data-height="400" class="popup">Latest Posts</a></li> i'm just starting out with js/jq. i dont know what's wrong. thanks for your help. p.s I have explicitly tried the onclick approach where I already gave the function a name followed by () between quotes but same thing happens. The link opens in the same window. There has to be a way to do what I want to do but I'm fugged iif I know how. Here's the problem... A page has three frames - top, left and disp. Top and left contain a number of buttons that display another page in disp. All the buttons need to behave as one set of radio buttons; when a button is clicked any other button returns to the non-clicked state. The really awkward bit is there's an image in top that changes depending on the currently clicked button and that image is behind the buttons. Here it is in pseudocode of sorts. Code: On click button[n]
Button[LastClicked].Image := Button[LastClicked].UnClickedImage;
Button[n].Image := Button[n].ClickedImage;
Top.Image := Button[n].TopImage;
end;
I hope that makes sense. If some kind soul has any idea of how to do that I'd be very grateful. Thanks. Simon. I tried posting this: <button type="button" onclick="JavaScript:alert('Let's assume.....')"> <img src="question.jpg" alt="Click here" /> <br />Click for Answer!</button> and it shows the button with the picture, but I am unable to click it. Can you please help me? Thank you in advance. Hey guys I'm new to Javascript and need some help with this code Code: <HTML> <HEAD> <TITLE>Swap Test</TITLE> </HEAD> <BODY> <script type="text/javascript"> var numberOne; var numberTwo; // Declaring the values of numberOne and numberTwo var numberOne = 9; var numberTwo = 1; // Variables are swapped numberOne = numberTwo; numberTwo = numberOne; // Output is displayed on-screen document.write (numberOne); document.write (numberTwo); </script> </BODY> </HTML> What I need to do is to declare the two variables, swap their values and then show the results on the screen. ...but it's not working, any ideas? Thanks! x Hey! First off you guys rock! Second im a massive noob - like beyond noob. Ok so heres the deal guys and gals: I use Kampyle (a feedback form thing) and when my viewers click my feedback button a new window pops up and is the form. Like this (plus thats my site if you want to try it): However! theres this site (yes my arch enemy, well were actually two different things and hey i dont even speak their language) and they use the same feedback thing by Kampyle too. But the catch is theirs is inbuilt. something like Lightbox Javascript but for forms/windows. or Facebook's popup notices? so theirs looks like this: This make me ANGRY!!! cause i want that and ive had to ask stupid people cause you guys and gals are way too advance for me... well i am only 17... anywho... WHO CAN HELP ME??? if you want to test the difference between the two forms, my site: that creative corner and click the feedback button. their site:Lyoness and click the feedback button in the bottom right corner. THANK YOU SO MUCH!!! hi all i'm kind of new to the JS world and need your help with some thing i hope it not that big to ask. if you go to linkedin website with your user (www.linkedin.com) you will see a bar called LinkedIn Today. what i need is this kind of bar but with messages changing all the time(moving) is this some thing i need to write from scratch or there some example that i can use? any help will be good for me now because i need to do it ASAP regards,shay Ok so before you help, just letting you know i'm a BIG noob at coding so please give noob friendly instructions, that would be great thanks I also googled and it didn't help so don't ask. Ok so I'm sure a few people here have heard of the game minecraft? well someone i know (distant relation) showed me something that will track players in the game on servers and i just need help to get it working. He told me i need node js installed to get it working which i don't know how to do (I'm on a mac). I did install python because some people told me i need python to install node js but I'm not sure. So pretty much how do i get node js installed and after that, how do i get the player tracker thing working? heres the github url for the player tracker: https://github.com/koryk/griefguild Much appreciated to anyone that helps! I'm a nooblet so go easy and thank you! |
|||||||