Solved

Force Selection From Checkbox Option

Posted on 2013-01-23
6
421 Views
Last Modified: 2013-01-30
Hello,

We have a list of check box options that goe like this as part of a web form:

Please select 3 companies:
(checkbox1)  Company 1
(checkbox2)  Company 2
(checkbox3)  Company 3
(checkbox4)  Company 4
(checkbox5)  Company 5

Here is the sample code
<table>
<tr><td align="right">Please select 3 Companies</td></tr>
<tr><td><input name="chkCompany1" type="checkbox" id="chkCompany1" value="Company 1">Company 1</td></tr>
<tr><td><input name="chkCompany2" type="checkbox" id="chkCompany2" value="Company 2">Company 2</td></tr>
<tr><td><input name="chkCompany3" type="checkbox" id="chkCompany3" value="Company 3">Company 3</td></tr>
<tr><td><input name="chkCompany4" type="checkbox" id="chkCompany4" value="Company 4">Company 4</td></tr>
<tr><td><input name="chkCompany5" type="checkbox" id="chkCompany5" value="Company 5">Company 5</td></tr>   
</table>

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This is what we look to acomplish.

1. The user must select 3 out of the 5 in order to succesfully submit the form.

2. The user should be notified if they do not select any checkbox or if they selected less than 3 when they click on the submit button.

3. If possible, when a user selects 3 checkboxes, the other 2 should grey out.

Thanks!  Your help is much appreciated.
0
Comment
Question by:JParra72
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6 Comments
 
LVL 82

Accepted Solution

by:
leakim971 earned 500 total points
ID: 38812098
test page : http://jsfiddle.net/AHm9u/
window.onload = function() {

    document.getElementById("myform").onsubmit = function() {
		var howManyChecked = nbCheckboxChecked();
        if(howManyChecked!=3) {
            alert("select 3 checkboxes, no more no less!");
        	return false;
        }
        return true;
    }

    var inputs = document.getElementsByTagName("input");
    for(var i=0;i<inputs.length;i++)  if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) ) inputs[i].onclick = function() {
        if(nbCheckboxChecked()==3) disableCheckboxes(true);
        else disableCheckboxes(false);
    };
}

function nbCheckboxChecked() {
    n = 0;
	var inputs = document.getElementsByTagName("input");
    for(var i=0;i<inputs.length;i++) if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) && inputs[i].checked ) n++; 
    return n;
}

function disableCheckboxes(b) {
	var inputs = document.getElementsByTagName("input");
	for(var i=0;i<inputs.length;i++) if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) ) inputs[i].disabled = !inputs[i].checked && b;
}

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0
 
LVL 82

Expert Comment

by:leakim971
ID: 38812134
with jQuery : http://jsfiddle.net/AHm9u/2/
$(document).ready(function() {
    $("form").submit(function(evt) {
        if($(":checkbox[name^=chkCompany]").length != 3) {
            evt.preventDefault();
            alert("select 3 checkboxes, no more no less!");
        }
    })
    $(":checkbox[name^=chkCompany]").change(function() {
        $(":checkbox[name^=chkCompany]:not(:checked)").prop("disabled", ($(":checkbox[name^=chkCompany]:checked").length == 3));
    })
})

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0
 
LVL 18

Expert Comment

by:nap0leon
ID: 38812157
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
	<title>Q_28006343.html</title>
</head>
<script>
function countCheckmarks() {
	var numCheckedBoxes = 0
	for (var i = 1; i<=5 ; i++) {
		if (document.getElementById('chkCompany'+i).checked == true ) {
			numCheckedBoxes = numCheckedBoxes  + 1;
		}
	}
	return numCheckedBoxes;
}

function validate(){
	var numCheckedBoxes = countCheckmarks()
	if ( numCheckedBoxes == 3 ) {
		document.getElementById('myForm').submit();
	} else {
		alert('You selected ' + numCheckedBoxes + '\nYou need to select 3.');
		return false;
	}

}

function checkMaxChecked() {
	if (countCheckmarks() == 3) {
		for (var i = 1; i<=5 ; i++) {
			if (document.getElementById('chkCompany'+i).checked == false ) {
				document.getElementById('chkCompany'+i).disabled = true;
			}
		}
	} else {
		for (var i = 1; i<=5 ; i++) {
			document.getElementById('chkCompany'+i).disabled = false;
		}
	}
}
</script>

<body>

<form name="myForm" id="myForm" method="GET" action="somenewpage.html">
<table>
	<tr><td align="right">Please select 3 Companies</td></tr>
	<tr><td><input name="chkCompany1" type="checkbox" id="chkCompany1" value="Company 1" onchange="checkMaxChecked();">Company 1</td></tr>
	<tr><td><input name="chkCompany2" type="checkbox" id="chkCompany2" value="Company 2" onchange="checkMaxChecked();">Company 2</td></tr>
	<tr><td><input name="chkCompany3" type="checkbox" id="chkCompany3" value="Company 3" onchange="checkMaxChecked();">Company 3</td></tr>
	<tr><td><input name="chkCompany4" type="checkbox" id="chkCompany4" value="Company 4" onchange="checkMaxChecked();">Company 4</td></tr>
	<tr><td><input name="chkCompany5" type="checkbox" id="chkCompany5" value="Company 5" onchange="checkMaxChecked();">Company 5</td></tr>   
</table>
<input type="button" value="submit" onclick="validate();"/>
</form>                                  

</body>
</html>

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0
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An important part of learning any new piece of software is understanding the terminology it uses. Thankfully WordPress uses fairly simple names for everything that make it easy to start using the software.

 
LVL 110

Expert Comment

by:Ray Paseur
ID: 38813032
On the server side in PHP, you can make a test if you change the names of the input controls like this. Instead of  name="chkCompany1", name="chkCompany2", etc.  You can use an array like this:  name="chkCompany[1]", name="chkCompany[2]", etc.

You can use var_dump() to print out the contents of $_POST to see the new data structure.

HTH, ~Ray
0
 

Author Closing Comment

by:JParra72
ID: 38827525
Worked like a charm!
0
 

Author Comment

by:JParra72
ID: 38837441
Hello,

I just noticed it will not work in IE 9 or firefox.

<script language="javascript" type="text/javascript">
window.onload = function() {

    document.getElementById("join_gold_form_c").onsubmit = function() {
		var howManyChecked = nbCheckboxChecked();
        if(howManyChecked!=3) {
            alert("select 3 checkboxes, no more no less!");
        	return false;
        }
        return true;
    }

    var inputs = document.getElementsByTagName("input");
    for(var i=0;i<inputs.length;i++)  if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) ) inputs[i].onclick = function() {
        if(nbCheckboxChecked()==3) disableCheckboxes(true);
        else disableCheckboxes(false);
    };
}

function nbCheckboxChecked() {
    n = 0;
	var inputs = document.getElementsByTagName("input");
    for(var i=0;i<inputs.length;i++) if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) && inputs[i].checked ) n++; 
    return n;
}

function disableCheckboxes(b) {
	var inputs = document.getElementsByTagName("input");
	for(var i=0;i<inputs.length;i++) if( inputs[i].name && /^chkCompany\d$/.test(inputs[i].name) ) inputs[i].disabled = !inputs[i].checked && b;
}
</script>

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