2 questions regarding Dynamically created checkboxes

[Ondernemer]

Hi guys,

On my page I dynamically create different checkboxes.

<input type="checkbox" name="ch1" value="some value"> option 1
<input type="checkbox" name="ch2" value="some value"> option 2
<input type="checkbox" name="ch3" value="some value"> option 3
<input type="checkbox" name="ch4" value="some value"> option 4

The reason they have different names is because of a different script which
allows me to shift-select a range of checkboxes. (there are 200+ on a page).

My Questions:

1. How can I have an alertbox popup when NONE of the checkboxes are checked
and the user submits the form?
2. How could I have a "select all" option on these checkboxes?

Any help would be so much appreciated!

Ond.

[Ulrik Skovenborg]

Re: 2 questions regarding Dynamically created checkboxes

Ondernemer wrote:[color=blue]
> 1. How can I have an alertbox popup when NONE of the checkboxes are checked
> and the user submits the form?[/color]

Put this in the javascript-section:
function validate(frm) {
var valid = false;
for (i=0;i<frm.leng th;i++) {
if (frm.elements[i].type == "checkbox" && frm.elements[i].checked) {
valid = true;
break;
}
}
if (!valid) {alert("Please select at least one checkbox");}
return valid;
}

When you submit the form you can call this function and it will
determine whether at least one checkbox is checked:
<form action="page.ph p" onsubmit="retur n validate(this); ">
[color=blue]
> 2. How could I have a "select all" option on these checkboxes?[/color]
Try this function:
function selectAll(frm,c heckedStatus) {
for (i=0;i<frm.leng th;i++) {
if (frm.elements[i].type == "checkbox") {
frm.elements[i].checked = checkedStatus;
}
}
}

It runs through the form, finds the checkboxes and sets the
checkedstatus to whatever you want. You can call them from the form like
this:

<form action="page.ph p" onsubmit="retur n validate(this); ">
<input type="button" value="Select All"
onclick="select All(this.form,t rue);">
<input type="button" value="DeSelect All"
onclick="select All(this.form,f alse);">

[Ondernemer]

Re: 2 questions regarding Dynamically created checkboxes

You simply......... rock!

[Ulrik Skovenborg]

Re: 2 questions regarding Dynamically created checkboxes

Ondernemer wrote:[color=blue]
> You simply......... rock!
>[/color]

Well, thank you very much.

However, if you have the exact number of checkboxes and they have the
same type of name (i.e. "ch1","ch2" and so on) you could use this to
avoid running through the whole form:
<script type="text/javascript">
function validate(frm,nu m) {
var valid = false;
for (i=1;i<num;i++) {
if (frm.elements["ch"+i].checked) {
valid = true;
break;
}
}
if (!valid) {alert("Please select at least one checkbox");}
return valid;
}

function selectAll(frm,n um,checkedStatu s) {
for (i=1;i<=num;i++ ) {
frm.elements["ch"+i].checked = checkedStatus;
}
}
</script>

and start them just as before but with one more argument:
<form onsubmit="retur n validate(this,5 );">
<input type="button" value="Select All"
onclick="select All(this.form,5 ,true);">
<input type="button" value="DeSelect All"
onclick="select All(this.form,5 ,false);">

5 is the number of checkboxes - you probably should change that ;-)