User Inputed Math Functions?
Jan 8, 2012
Initiate function function count(form){Initiate vars
var answer=0;
var lower_limit;
var upper_limit;
var func;
should it not be parseInt? Maybe thats why.
parseInt(form.user_input.value)
[Code]...
As you can see by what im doing here, I'm trying to make it so that a person can enter a math expression in a form text box and based on what the user entered, javascript will compute the summation of the function.
What I'm truly asking here is, how do I make Javascript correctly compute the sum, based on what the unser inputed? Because when I enter for example, 1/x, a lower limit, and a upper limit, it just returns an answer of NaN. I'm one step away from building a Javascript function to compute the sum of any user inputed function. It's just the text parsing thats got me knocked down.
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Jul 23, 2005
Javascript has a very small math function list. However there is no
reason that this list can not be extended greatly. Speed is not an
issue, unless you nest complicated calculations several levels deep. In
that case you need much more ram than a PC has to store functions
calculated in loops so that you do not have to recalculate every time
you cycle through the nest of loops. Using a HD for storage to extend
ram is much too slow for many applications.
Some functions such as hyperbolic ones are easy to add, since they are
just simple combinations of the built in javascript math functions. I
have found a few examples on the web such as Bessel functions. I found
far fewer javascript math functions than I expected on Google searches.
Thus I have had to write several functions of my own.
See http://www.cwdjr.net/math/I0L0andI1L1.html for an example of two
"functions from hell" that are very difficult to evaluate. Fortunately
there are Fortran programs that can be used as a starting point. I was
able to modify the Fortran programs to work on javascript. I have used
these functions for technical applications in the past.
The page is set up to reject the NN 4 series, because it will not
support some of the script needed such as .toExponential(n) and
to.Fixed(n)for writing output in exponential or fixed format. I was
amazed that even the old MSNTV(former WebTV) set-top box, that no
longer is being made, will even support these output formats. I wonder
about IE4. If it will not support these output formats, I can easly
block it by checking for document.getElementById.
The code works properly on the latest versions of IE6, MSN9, Firefox,
Mozilla, Netscape, and Opera. I am not selling anything, so for a
special interest page such as this, I see no need to support older
browsers.
The advantage of doing math with javascript is that it is so portable.
You can do it anywhere you can use a computer, or you can do it on your
own local computer offline. There are several math programs for PCs
that will do very much more than you can hope to do with javascript.
Unfortunately the program I would like costs about US$ 1800. Also there
are versions you can install on a server, but these also are expensive.
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Nov 7, 2006
Code:
function finalSize(){
var size = document.getElementById('size').value;
var margin = document.getElementById('margins').value;
var mirrors = document.getElemntById('mirrorsRadio').value;
var size_array = size.split('x');
var h = size_array[0];
var w = size_array[1];
var finalH = ''
var finalW = ''
if(margin > 1){
finalH = h * margin;
finalW = w * margin;
document.getElementById('finalSize').value = finalH+'x'+finalW;
}else{
newH = h * margin;
newF = w * margin;
finalH = newH + h;
finalW = newW + w;
document.getElementById('finalSize').value = finalH+'x'+finalW;
}
}
I see it's ok, but it gives me this error:
Object doesn't support this property or method.
I don't know what I'm doing wrong. All I know is PHP, but from what little I learned on Javascript, my brain is telling me I'm right, but my experience is telling me I'm wrong. XD
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Feb 20, 2010
the program that i want to create will first let the user input how many execution he want to perform and will determine the highest and lowest number that he inputted.
for example.
prompt: how many execution you want to perform?
i type: 5
prompt:input number:10
prompt:input number:8
prompt:input number:5
[Code]....
but it only allows for the up to inputs[6] and the code is very long. i think i can use looping in it. but i dont know to use looping in math.min and math.max.
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Feb 4, 2009
I will have 1 html page which uses javascript it will validate the form so the information inputed is correct...then on submit it will load another page with form ect...however the second page depends on what was selected on the first page say a gender radiobutton was on the first page and they selected male then on the second page a male figure/picture would be displayed...now I can do this all on 1 page however when trying to do it on 2 different pages the second page can't read whats going on/has happened on the first page...
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Aug 1, 2011
Im trying to add a cross browser event listener to an element so i made my own function that detects weather the browser is IE or Firefox, then add the appropriate eventListener function to the element.
Code JavaScript:
// CROSS-BROWSER ADD EVENT HELPER METHODS
function addCrossBrowserEventListener (elementName, eventName, functionName) {
// does the addEventListener function exist?
[Code]....
but when i run the code inside Firefox i get a error message "name.addCrossBrowserEventListener is not a function".
So I'm wondering is it possible to add custom functions to elements directly or is there any special way of doing it.
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May 20, 2011
Ok so the following code works.
function myFunction(myName)
{
alert("You are "+myName);
}
callFunction = "myFunction";
parameter = "Joe";
[Code]...
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Dec 8, 2011
i need to ask the user for details about a car, i will not know how many cars are going to be stored and therefore need an array i think. I need the function for asking the user and will need to repeat the code later in a menu. at this stage i just want to ask the user for input, store it in array and use an alert to check if it works?
<html>
<script>
// Purpose: Gather car information and store it in a datbase
// Ask user for REG info, CAR MAKE, car VIN
var CarDetails = {
RegNum:"",CarMake:"", CarVin:"";
}
[Code]...
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Feb 22, 2011
how do you get a textbox in a form to retain an inputed value after that form is submitted
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May 21, 2007
Anyone any idea why the Math.abs() isn't working in this code? I
thought it was supposed to convert negative numbers to whole numbers?
var se = [-27, -27, -27];
var time = 100
if(se[0] < 0){
Math.abs(se[0]); //<-- this isn't converting it to a whole number
se[0] += 1;
se[0] = (se[0]/(time / 4));
}
The result I get is -1.04 when it should be 1.12
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Jul 20, 2005
I remember there is a programming language where you can initialize the
random number generator, so that it can - if you want - give you the exactly
same sequence of random numbers every time you initialize it with the same
parameter. Can this be done with JavaScript? I couldn't find anything in the
documentation. Basically, what I want to achieve is to obtain always the
same sequence of random numbers for the same given initialization value (but
of course different sequences for different init values).
Can this be done in JavaScript?
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Mar 5, 2010
why I am getting Nan
<script type="text/javascript">
var num1;
var num2;
var num3;
[Code]....
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Jun 18, 2010
<script type="text/javascript">
function countItDown(){
var current=parseFloat(document.getElementById("currentsecondscount").value);
var seconds=current;
document.getElementById("debug").innerHTML="S "+current;
var minutes=Math.floor(seconds/60);
[Code]...
im not sure why Firefox is doing this. it seems to work fine on Firefox 3.6.3 for Mac.
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Nov 23, 2010
I have this simple manual photo slide show. It shows four photos and when you click the next button and it moves one photo over and one photo back for the previous button. I have to moving by changing the CSS property of 'left' by 195 pixels each move. So for it to move next it will subtract 195 pixels from the left property and for moving back it add 195 pixels to the left property. I have the code setup so when you click it changes the property of left to either -195 or 195 pixels but I need it so it actually does the math, not just give it a set value. But I don't know how to do that.code...
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Feb 10, 2011
I have a website that allows users to enter complex mathematical formulas into a text field and evaluates them.
I am currently using eval() because it not only can handle all the standard mathematical functions, but also gives them access to the Math object. That way the users can use functions such as Math.max() and everything else.
I realize, though, that using eval is evil, I assume because a malicious user might throw in some more damaging javascript that would be run without checking it. (That's why eval is evil, right?)
Is there a way that I can allow my users to construct complex mathematical formulas and use the Math object (or an equivalent) without potentially opening my site up to harm?
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Nov 8, 2011
Just started to learn java & came up with the following, but can't get the math.round to work. Anyone able to tell me where I'm going wrong please ? code...
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Nov 10, 2005
If I have the following
2^n=a
javascript:Math.pow(2,n)=a;
and I now a how do I then find n with javascript?.
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Nov 12, 2010
I have 3 divs. I want distribution them random (when refresh the windows, three divs' position will be changed)
I think Math random() can solve this problem, but how to do that? code...
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Jan 21, 2005
i have a column which have some numbers into...
and any td of this columns have class="something"...
so i want to sum the tds of that column which have the same class name when i click on the first cell..
ie
Code:
+---+
| | -> i click here
+---+
| 3 | -> class="ha"
+---+
| 4 | -> class="haha"
+---+
| 2 | -> class="ha"
+---+
| 8 | -> class="haha"
+---+
so here i want the sum in this column where the class name is "ha"...
so the sum is 3+2 = 5...
all that have to happens when i click on the first cell!
any suggestion??
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Feb 15, 2012
I have following codes
<html><head>
<title>this is first math exercise within Java Script</title>
<script lanuage="Javascript">
function total(){
Var amount1 = text1.value
Var amount2 = text2.value
Var total=eval(amount1) + eval(amount2)
text3.value=total
alter("Correct Answer")
} </script>
</head><body><center><form>
<table width="20%" border="1" cellpadding="1" cellspacing="1" >
<tr><td width="10%" align="center">Amount1</td>
<td width="10%"><input type="number" name="text1" value="" min="1001" max="8000"></td>
</tr><tr><td width="10%" align="center">Amount2</td>
<td width="10%"><input type="number" name="text2" value="" min="1001" max="8000"></td>
</tr><tr><td width="10%" align="center">Total</td>
<td width="10%"><input type="number" name="text3" value="" min="1001" max="8000""></td>
</tr><tr><td width="10%"></td>
<td width="10%"><INPUT TYPE="button" NAME="Submit" VALUE="Compute" onclick="total()">
<input type=reset Value="Clear" size="30"></td></tr>
</table></form></center></body></html>
I want to get summed value in text3 but function does not execute.
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Jun 9, 2009
I'm trying to write a function that does a simple math function between some textfields.
There are 4 variables : Unit price, Discount, Quantity and Total
Unit price is a fixed variable.
Discount, Quantity and Total depend on the fixed variable and also on the values of eachother. (ie : if qty=2 then total=2xUnit Price) etc...
I want to be able to show the changing values in real time.
So if I have 3 textfields and I change qty, I want it to update Total based on the discount and the qty. If I update discount, I want to update Total based on qty and discount.
I'm guessing I would have to write three functions and call each one from their respective textfields.
How to write a function, and call it so that passes the unit price to the funtion, gets the values of all of the textfields and then changes them all to their new values?
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Mar 10, 2010
Either I made an uh-oh, or there is a serious problem with Javscripts math functions. Math.sin(x) returns the sine of x in radians. Last time I checked, the sine of pi radians is 0, but in javascript:
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Dec 14, 2007
Well, it's been a while since I last visited CF, but I'm finally back and, for the life of me, am drawing a total blank on something that seems like it should be fairly easy to handle.
The Math.sqrt() function works just fine if all a person needs is the Square Root of a number, but what about needing the Cube Root or even a 4th Root of a number?
My first instinct was to use the Math.pow(x,y) function with a negative value for "y." For instance;
var z=Math.pow(27,-3)
This should return a value of 3. Unfortunately, this doesnt seem to work when I tested it through the W3 reference pages, so I am looking for a clue as to how I might go about finding such values, or if it is even possible through Javascript.
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Jun 20, 2011
The last line gives an utterly ridiculous number (two 4-digit negative numbers for minutes and seconds) rather than the minutes and seconds it should. My commented example calculations are shown to the right of the lines. Scenario: A race car driver enters in the length of the race and how long he can drive before he runs out of gas (runtime). He also enters how much time he expects to spend in the pit area for each pit stop. Purpose: This calculation tells him how many equally spaced pit stops he'll need to make throughout the race, and the amount of time driving between pit stops (interval quantity).. The code check passes in JSHint.com
[Code]...
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May 22, 2011
So I created a long while back a basic debt calculator for a blogger-client of mine. Here's the relevant code:
Code:
<script language="JavaScript" type="text/javascript"><!--
function addCommas(nStr)
{
nStr += '';
x = nStr.split('.');
x1 = x[0];
[Code]...
This code just does some basic arithmetic based on the values the client gave me, and it works fine in pretty much every browser, but for some reason in some web-kit (I think)-based browsers (Safari 5.x on the PC as well as a few other similar rarely-used browsers like Konq on Linux according to browsershots), the final tally (perperson2) does not display. [URL]...
I'm not a JavaScript wizard, but this is pretty basic stuff -- am I missing something really obvious?
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Dec 8, 2010
I am having some trouble trying to fix my math equation to calculate the total rent by aquiring values from my form fields. Converting the date fields to days and finding the number of days via two date fields is mainly where I am having trouble. Also, I am trying to have a window pop up before submission but the onclick event does not seem to function properly.Below is the math equation I have come up with:
//calculate days from date field
function calcTotal(date1, date2) {
//assign variables
[code]....
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