passing a variable - Javascript

Geoff

As a newbie to javascript can someone tell me please how to pass a variable from HTML to Javascript?

I have the following script which works OK if I input to str from the "prompt" box, but I want to input from a one-line text box on an HTML page.

Thanks in advance.

Geoff.

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>New Page 1</title>
</head>
<body>
<script type = "text/javascript">
// Input number
var str = null;
if ( str == null );
var str = prompt( "Enter number", "" );
var num2 = str.substr(0,3);
var res = +num2;
// Test for correctness
if(res == 123) alert ("This will work OK");
else
if(res == 124) alert ("This will work OK");
else
if(res == 128) alert ("This will work OK");
else
alert (" Unfortunately, this will not work");
</script>
</body>
</html>

Jan 22 '06 #1

Subscribe Post Reply

1348

Ian Collins

Geoff wrote:

As a newbie to javascript can someone tell me please how to pass a
variable from HTML to Javascript?

I have the following script which works OK if I input to str from the
"prompt" box, but I want to input from a one-line text box on an HTML
page.

You have to use the DOM to locate the element (hint -give it a name or
id attribute), then read it's value.

--
Ian Collins.

Jan 22 '06 #2

Hal Rosser

Assume the text box is named "inBox" and it is in a form named "form1"

var theValue = document.form1.inBox.value;
or
var theValue = document.forms[0].elements[0].value; //assuming the text box
is the first element in the form.

You'll probably want to add a button to generate a onclick so you can call
the function.

Jan 23 '06 #3

Geoff

Thanks guys, that's great!
"Geoff" <so*****@somewhere.sometime> wrote in message news:dr**********@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...
As a newbie to javascript can someone tell me please how to pass a variable from HTML to Javascript?

Jan 23 '06 #4

Similar topics

passing values in a setTimeout function

by: domeceo | last post by:

can anyone tell me why I cannot pass values in a setTimeout function whenever I use this function it says "menu is undefined" after th alert. function imgOff(menu, num) { if (document.images) {...

Javascript

Passing an array of chars to a function

by: jr | last post by:

Sorry for this very dumb question, but I've clearly got a long way to go! Can someone please help me pass an array into a function. Here's a starting point. void TheMainFunc() { // Body of...

C / C++

Passing arguments to function by reference - Good or Bad?

by: Mike MacSween | last post by:

Just spent a happy 10 mins trying to understand a function I wrote sometime ago. Then remembered that arguments are passed by reference, by default. Does the fact that this slowed me down...

Microsoft Access / VBA

Problem passing custom object between forms

by: Scott Zabolotzky | last post by:

I'm trying to pass a custom object back and forth between forms. This custom object is pulled into the app using an external reference to an assembly DLL that was given to me by a co-worker. A...

ASP.NET

VB-101: Passing Arrays ByVal vs ByRef

by: John Pass | last post by:

Hi, In the attached example, I do understand that the references are not changed if an array is passed by Val. What I do not understand is the result of line 99 (If one can find this by line...

Visual Basic .NET

lock and object passing by ref

by: MSDNAndi | last post by:

Hi, I get the following warning: "Possibly incorrect assignment to local 'oLockObject' which is the argument to a using or lock statement. The Dispose call or unlocking will happen on the...

C# / C Sharp

Passing arguements by reference

by: Andrew Bullock | last post by:

Hi, I have two classes, A and B, B takes an A as an argument in its constructor: A a1 = new A(); B b = new B(a1);

C# / C Sharp

Passing a Variable from one web site to another for ASP

by: James Robertson | last post by:

I am new to the ASP and VB thing so be kind. Question I have is that I have created an ASPX web site to use as an E-Mail page. But I want to use this for a lot of users. Can I create the link on...

Visual Basic .NET

Passing a byte[] by ref, and here I thought I knew what was going on.

by: DaTurk | last post by:

If I call this method, and pass it a byte by ref, and initialize another byte array, set the original equal to it, and then null the reference, why is the original byte array not null as well? I...

C# / C Sharp

Passing long Strings as parameters (by ref and by value)

by: =?Utf-8?B?U3VqZWV0?= | last post by:

If there are long strings (like 1MB or 2MB) is it more performant to pass those by ref to methods or by value?

C# / C Sharp

Easy Steps to Fix "Canon Printer Won't Connect to WiFi Network"

by: taylorcarr | last post by:

A Canon printer is a smart device known for being advanced, efficient, and reliable. It is designed for home, office, and hybrid workspace use and can also be used for a variety of purposes. However,...

General

How to turn on java script in a villaon keypad mobile phone

by: Charles Arthur | last post by:

How do i turn on java script on a villaon, callus and itel keypad mobile phone

Java

Batch import of multiple excel files into the database

by: ryjfgjl | last post by:

If we have dozens or hundreds of excel to import into the database, if we use the excel import function provided by database editors such as navicat, it will be extremely tedious and time-consuming...

Data Management

Merging data from multiple Excel files

by: ryjfgjl | last post by:

In our work, we often receive Excel tables with data in the same format. If we want to analyze these data, it can be difficult to analyze them because the data is spread across multiple Excel files...

Data Management

Migrating Website to Cloud - Emmanuel Katto

by: emmanuelkatto | last post by:

Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel

General

Looking to do Android software development, any suggestions? Is flutter better?

by: nemocccc | last post by:

hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?

General

Is that possible of reading the .csv file in column wise and the column have different lengths ?

by: Sonnysonu | last post by:

This is the data of csv file 1 2 3 1 2 3 1 2 3 1 2 3 2 3 2 3 3 the lengths should be different i have to store the data by column-wise with in the specific length. suppose the i have to...

C / C++

What is ONU?

by: marktang | last post by:

ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...

General

The easy way to turn off automatic updates for Windows 10/11

by: Hystou | last post by:

Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows...

Windows Server