Modify Cryptic Error Message for Check box in VF Page

Question

Hi I have following code for visual force and apex controller to render the checkbox. I have marked the checkbox as required="true". When I try to submit the page it give me cryptic error message.

Error Message:

j_id0:SPE: Validation Error: Value is required.

How do I modify this error message?

<apex:selectCheckboxes value="{!RegPeriod}" required="true" id="RegPerdId">
                    <apex:selectOptions value="{!RegistrationPeriod}"/> 
</apex:selectCheckboxes>

Apex Controller:

public List<String> regPeriod = new List<String>();
    public List<String> getRegPeriod(){
        return regPeriod;
    } 
    public void setRegPeriod(List<String> RegPrd){
        regPeriod.addAll(RegPrd);
    }

public List<SelectOption> RegistrationPeriod {
        get {
            List<SelectOption> listOfRegPeriod = new List<SelectOption>();
            for(S_Period__c certiPeriod : listPeriod) {
                listOfRegPeriod.add(new SelectOption( certiPeriod.Id, certiPeriod.Name));
            }
        return listOfRegPeriod;
        }
        set;
    }

Answer 1

Specify a label attribute for your input elements. Example provided below.

Controller

public class reqchk {
    public reqchk() {
        values = new String[0];
    }
    public String[] values { get; set; }
    public SelectOption[] getOptions() {
        SelectOption[] results = new SelectOption[0];
        for(String item: 'Value A;Value B;Value C;Value D'.split(';')) {
            results.add(new SelectOption(item, item));
        }
        return results;
    }
}

Page

<apex:page controller="reqchk">
    <apex:form>
        <apex:pageMessages />
        <apex:selectCheckboxes label="Value Selections" required="true" value="{!values}">
            <apex:selectOptions value="{!options}" />
        </apex:selectCheckboxes>
        <apex:commandButton value="Submit" />
    </apex:form>
</apex:page>

Note that you won't see the label unless you include the element in a page block, however... but the error message will be correct.