Dynamic checkbox with Javascript

S

Steph

Hello,

Can someone tell me the script to use for having a change on the same page
when using checkbox function ?

For example, i would to check one condition and display dynamically a button
if the condition is checked on the same page.

Thanks in advance for your help

Steph
 
R

RobG

Steph wrote:
[...]
For example, i would to check one condition and display dynamically a button
if the condition is checked on the same page.
Click to expand...

The script below uses an onload function to fire the click when the
document loads. This is for two reasons:

1. If the user has javascript disabled or their browser does not
support it, the text box will still display and they can use it.
Otherwise, it will not be shown when the checkbox is checked.

2. You can set the checkbox to checked or not and the text input will
display/not display on opening the page without you having to change
the properties of the checkbox.

One note of caution: if the user puts something into the input then
unchecks the checkbox, the inupt is hidden but the text in it will
still be submitted. So maybe you want to disable it when it is not
displayed.

You can also use:

inp.style.visibility = 'visible' or 'hidden'

if you want the text box to still take up space on the page when
hidden.

Lastly, if the page is big, the onload will fire after all content is
loaded, so your text box may appear the disappear. To prevent that,
move the onload to a script immediately after the input so the body tag
becomes:

<body>

and put:

<script type="text/javascript">
clickIt('aForm','aCheckbox');
</script>

immediately after the text input. I think putting it in the body
onload is cleaner, but obviously having the input flash on then off may
be disconcerting for users.



<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html><head>
<title>Dynamic text box</title>
<script type="text/javascript">
function showHide(chk,inp){
if (chk.checked) {
inp.style.display = '';
} else {
inp.style.display = 'none';
}
}

function clickIt(frm,chk) {
var x = document.forms[frm].elements[chk];
if (x) x.click();
}
</script>
</head>
<body onload="clickIt('aForm','aCheckbox');">
<form action="" name="aForm">
<label for="aCheckbox">Click me&nbsp;<input type="checkbox"
name="aCheckbox" id="aCheckbox" onclick="
showHide(this,this.form.txtInput);
">
</label><br>
<input type="text" size="30" name="txtInput">
</form>
</body></html>
 
R

Robert

Steph said:
For example, i would to check one condition and display dynamically a button
if the condition is checked on the same page.
Click to expand...

This may help:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<META http-equiv="content-type" content="text/html; charset=iso-8859-1">
<title>Radio buttons</title>

<script type="text/javascript">

function validate(x)
{
var checkedButton;

// Figure out which radio button was pressed

checkedButton = findValue(x.receiveVia);

var varName = x.theName.value;
var varEmail = x.theEmail.value;
var varAddress = x.theAddress.value;

// I changed submitOK to a boolean variable.
var submitOK = true;

// Validate email: name and email

if (checkedButton == "byEmail")
{

if (varName == '')
{
alert("Please fill in your Name");
submitOK = false;
}
if (varEmail == '')
{
alert("Please fill in Email");
submitOK = false;
}
if (varAddress != '')
{
alert("Please erase the address field.");
submitOK = false;
}

return submitOK;

}

// Validate print: name, email, and address

else if (checkedButton=="printed")
{
// Error message should be in the order on the form
if (varName.length == '')
{
alert("Please fill in your Name");
submitOK = false;
}
if (varEmail == '')
{
alert("Please fill in Email");
submitOK = false;
}
if (varAddress == '')
{
alert("You must enter your Address");
submitOK = false;
}

return submitOK;
}
else
{
alert("You need to select either email or print.");
return false;
}

}

function vanishHidden(doWhat)
{
// Check if the getElementById method is available
if (document.getElementById)
{
document.getElementById("hideSpan").style.display = doWhat;
}
else if (document.all)
{
alert("Running an older version of IE.");
document.all.hideSpan.style.display = doWhat;
}
else
{ alert("Cannot change visibility of address field"); }
}


function hideHidden(doWhat)
{
// Check if the getElementById method is available
if (document.getElementById)
{
document.getElementById("vanishSpan").style.visibility = doWhat;
}
else if (document.all)
{
alert("Running an older version of IE.");
document.all.vanishSpan.style.visibility = doWhat;
}
else
{ alert("Cannot change display value of address field"); }
}

// See which radio button is selected and return its value
function findValue(obj)
{
var i, theValue;
theValue = null;

for (i=0;i<obj.length;i++)
{
if (obj.checked == true)
{
theValue = obj.value;
break;
}
}

return theValue;
}
</script>

</head>

<body>

<p>Please try out our form.</P>
<P>This form uses the CSS display
and visibility style attributes. When you click on the
radio button email, Javascript code uses the display attribute
property of hidden to exclude the address field from the display.
No space will be taken up in the window.
When you click on the no radio button, Javascript code uses the
visibility attribute property of none to make the literature
catagories invisible. Space will be taken up in the window.</p>

<form name="myForm"
action="http://www.notavalidurl.com"
method="GET"
onsubmit="return validate(document.forms['myForm']);">
<p>
<input type="radio"
name="receiveVia"
value="printed"
onclick="vanishHidden('');">
Printed brochure</p>
<p>
<input type="radio"
name="receiveVia"
value="byEmail"
onclick="vanishHidden('none');
document.forms['myForm'].theAddress.value = '';">
Via Email</p>
<p>Name:<br>
<input type="text"
name="theName"
size="20"><br><br>
Email:<br>
<input type="text" name="theEmail" size="20">
<br><br>

<span id="hideSpan">
Postal address:<br>
<input type="text" name="theAddress" size="40">
</span>
</p>
<p>
Do you wish to receive additional literature?
<br>
<input type="radio"
name="literature"
value="yes"
onclick="hideHidden('visible')";>&nbsp;Yes&nbsp;&nbsp;
<!-- use visibility. -->
<span id="vanishSpan">
<input type="checkbox"
name="gardening"
valuegardening>&nbsp;Gardening
<input type="checkbox"
name="kitchen"
valuekitchen>&nbsp;Kitchen
<input type="checkbox"
name="vacation"
valuevacation>&nbsp;Vacation
<!-- Just get it done. I know there are better ways. -->
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<input type="checkbox"
name="office"
valueoffice>&nbsp;Office
<input type="checkbox"
name="secondhome"
valuesecondhome>&nbsp;Second Home
</span>

<br>
<input type="radio"
name="literature"
value="no"
onclick="hideHidden('hidden');
var d=document.forms['myForm'];
d.elements['gardening'].checked=false;
d.elements['kitchen'].checked=false;
d.elements['vacation'].checked=false;
d.elements['office'].checked=false;
d.elements['secondhome'].checked=false;">
No
</p>
<p><input type="submit"
border="0"
value="Submit form"
width="75"
height="17"
ALT="Submit button"></p>

</form>

<script type="text/javascript">
// In the case of a reload, the radio button may already be clicked.
// This code needs to be after the form.
var x = document.forms["myForm"];
if (x.receiveVia[0].checked == true)
{ vanishHidden('');}
else if (x.receiveVia[1].checked == true)
{ vanishHidden('none');}
else
{ ;}

if (x.literature[0].checked == true)
{ hideHidden('visible');}
else if (x.literature[1].checked == true)
{ hideHidden('hidden');}
else
{ ;}

</script>
</body>
</html>


Robert
 
S

Steph

RobG said:
Steph wrote:
[...]
For example, i would to check one condition and display dynamically a
button if the condition is checked on the same page.
Click to expand...

The script below uses an onload function to fire the click when the
document loads. This is for two reasons:

1. If the user has javascript disabled or their browser does not
support it, the text box will still display and they can use it.
Otherwise, it will not be shown when the checkbox is checked.

2. You can set the checkbox to checked or not and the text input will
display/not display on opening the page without you having to change
the properties of the checkbox.

One note of caution: if the user puts something into the input then
unchecks the checkbox, the inupt is hidden but the text in it will
still be submitted. So maybe you want to disable it when it is not
displayed.

You can also use:

inp.style.visibility = 'visible' or 'hidden'

if you want the text box to still take up space on the page when
hidden.

Lastly, if the page is big, the onload will fire after all content is
loaded, so your text box may appear the disappear. To prevent that,
move the onload to a script immediately after the input so the body tag
becomes:

<body>

and put:

<script type="text/javascript">
clickIt('aForm','aCheckbox');
</script>

immediately after the text input. I think putting it in the body
onload is cleaner, but obviously having the input flash on then off may
be disconcerting for users.



<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html><head>
<title>Dynamic text box</title>
<script type="text/javascript">
function showHide(chk,inp){
if (chk.checked) {
inp.style.display = '';
} else {
inp.style.display = 'none';
}
}

function clickIt(frm,chk) {
var x = document.forms[frm].elements[chk];
if (x) x.click();
}
</script>
</head>
<body onload="clickIt('aForm','aCheckbox');">
<form action="" name="aForm">
<label for="aCheckbox">Click me&nbsp;<input type="checkbox"
name="aCheckbox" id="aCheckbox" onclick="
showHide(this,this.form.txtInput);
">
</label><br>
<input type="text" size="30" name="txtInput">
</form>
</body></html>
Click to expand...

Thanks Rob,
I will test and let you know ...
Steph
 
S

Steph

Robert said:
Steph said:
For example, i would to check one condition and display dynamically a
button
if the condition is checked on the same page.
Click to expand...

This may help:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<META http-equiv="content-type" content="text/html; charset=iso-8859-1">
<title>Radio buttons</title>

<script type="text/javascript">

function validate(x)
{
var checkedButton;

// Figure out which radio button was pressed

checkedButton = findValue(x.receiveVia);

var varName = x.theName.value;
var varEmail = x.theEmail.value;
var varAddress = x.theAddress.value;

// I changed submitOK to a boolean variable.
var submitOK = true;

// Validate email: name and email

if (checkedButton == "byEmail")
{

if (varName == '')
{
alert("Please fill in your Name");
submitOK = false;
}
if (varEmail == '')
{
alert("Please fill in Email");
submitOK = false;
}
if (varAddress != '')
{
alert("Please erase the address field.");
submitOK = false;
}

return submitOK;

}

// Validate print: name, email, and address

else if (checkedButton=="printed")
{
// Error message should be in the order on the form
if (varName.length == '')
{
alert("Please fill in your Name");
submitOK = false;
}
if (varEmail == '')
{
alert("Please fill in Email");
submitOK = false;
}
if (varAddress == '')
{
alert("You must enter your Address");
submitOK = false;
}

return submitOK;
}
else
{
alert("You need to select either email or print.");
return false;
}

}

function vanishHidden(doWhat)
{
// Check if the getElementById method is available
if (document.getElementById)
{
document.getElementById("hideSpan").style.display = doWhat;
}
else if (document.all)
{
alert("Running an older version of IE.");
document.all.hideSpan.style.display = doWhat;
}
else
{ alert("Cannot change visibility of address field"); }
}


function hideHidden(doWhat)
{
// Check if the getElementById method is available
if (document.getElementById)
{
document.getElementById("vanishSpan").style.visibility = doWhat;
}
else if (document.all)
{
alert("Running an older version of IE.");
document.all.vanishSpan.style.visibility = doWhat;
}
else
{ alert("Cannot change display value of address field"); }
}

// See which radio button is selected and return its value
function findValue(obj)
{
var i, theValue;
theValue = null;

for (i=0;i<obj.length;i++)
{
if (obj.checked == true)
{
theValue = obj.value;
break;
}
}

return theValue;
}
</script>

</head>

<body>

<p>Please try out our form.</P>
<P>This form uses the CSS display
and visibility style attributes. When you click on the
radio button email, Javascript code uses the display attribute
property of hidden to exclude the address field from the display.
No space will be taken up in the window.
When you click on the no radio button, Javascript code uses the
visibility attribute property of none to make the literature
catagories invisible. Space will be taken up in the window.</p>

<form name="myForm"
action="http://www.notavalidurl.com"
method="GET"
onsubmit="return validate(document.forms['myForm']);">
<p>
<input type="radio"
name="receiveVia"
value="printed"
onclick="vanishHidden('');">
Printed brochure</p>
<p>
<input type="radio"
name="receiveVia"
value="byEmail"
onclick="vanishHidden('none');
document.forms['myForm'].theAddress.value = '';">
Via Email</p>
<p>Name:<br>
<input type="text"
name="theName"
size="20"><br><br>
Email:<br>
<input type="text" name="theEmail" size="20">
<br><br>

<span id="hideSpan">
Postal address:<br>
<input type="text" name="theAddress" size="40">
</span>
</p>
<p>
Do you wish to receive additional literature?
<br>
<input type="radio"
name="literature"
value="yes"
onclick="hideHidden('visible')";>&nbsp;Yes&nbsp;&nbsp;
<!-- use visibility. -->
<span id="vanishSpan">
<input type="checkbox"
name="gardening"
valuegardening>&nbsp;Gardening
<input type="checkbox"
name="kitchen"
valuekitchen>&nbsp;Kitchen
<input type="checkbox"
name="vacation"
valuevacation>&nbsp;Vacation
<!-- Just get it done. I know there are better ways. -->
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<input type="checkbox"
name="office"
valueoffice>&nbsp;Office
<input type="checkbox"
name="secondhome"
valuesecondhome>&nbsp;Second Home
</span>

<br>
<input type="radio"
name="literature"
value="no"
onclick="hideHidden('hidden');
var d=document.forms['myForm'];
d.elements['gardening'].checked=false;
d.elements['kitchen'].checked=false;
d.elements['vacation'].checked=false;
d.elements['office'].checked=false;
d.elements['secondhome'].checked=false;">
No
</p>
<p><input type="submit"
border="0"
value="Submit form"
width="75"
height="17"
ALT="Submit button"></p>

</form>

<script type="text/javascript">
// In the case of a reload, the radio button may already be clicked.
// This code needs to be after the form.
var x = document.forms["myForm"];
if (x.receiveVia[0].checked == true)
{ vanishHidden('');}
else if (x.receiveVia[1].checked == true)
{ vanishHidden('none');}
else
{ ;}

if (x.literature[0].checked == true)
{ hideHidden('visible');}
else if (x.literature[1].checked == true)
{ hideHidden('hidden');}
else
{ ;}

</script>
</body>
</html>


Robert
Click to expand...


Thanks again for your help !
Steph
 

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