/*
Validation script adapted from: http://onlinetools.org/articles/unobtrusivejavascript/chapter5.html
Good stuff.
*/

function checkform(of, element, ajaxFunction)
{
//clear element
        alert('of='+of+' element='+element+' fn='+ajaxFunction);
        var box = document.getElementById(element);

                //Cycle all The Children
                var kids = box.childNodes;
                for(i=0; i < kids.length; i++)
                        {
                                 //Quick test
                                 var jr = kids[i];
                                 //This should remove everything from the box
                                //GL box.removeChild(jr);
                        }

// Test if DOM is available and there is an element called required
        if(!document.getElementById || !document.createTextNode){return;}
        if(!document.getElementById('required')){return;}
// Define error messages and split the required fields
        var errorID='errormsg';
        var errorClass='error'
/* changes for linked list */
        var errorMsg='Please enter a valid value in to the following fields:';
/* end changes for linked list */
        var errorImg='images/error.gif';
        var errorAlt='Error';
        var errorTitle='This field has an error!';
        var reqfields=document.getElementById('required').value.split(',');

// Cleanup old mess
        // if there is an old errormessage field, delete it
        if(document.getElementById(errorID))
        {
                var em=document.getElementById(errorID);
                em.parentNode.removeChild(em);
        }
        // remove old images and classes from the required fields
        for(var i=0;i<reqfields.length;i++)
        {
                var f=document.getElementById(reqfields[i]);
                if(!f){continue;}
                if(f.previousSibling && /img/i.test(f.previousSibling.nodeName))
                {
                        f.parentNode.removeChild(f.previousSibling);
                }
                f.className='field';
        }
// loop over required fields
        for(var i=0;i<reqfields.length;i++)
        {
// check if required field is there
                var f=document.getElementById(reqfields[i]);
                if(!f){continue;}
// test if the required field has an error,
// according to its type
                switch(f.type.toLowerCase())
                {
                        case 'text':
                                if(f.value=='' && f.id!='email'){cf_adderr(f)}
// email is a special field and needs checking
                                if(f.id=='email' && !cf_isEmailAddr(f.value)){cf_adderr(f)}
                        break;
                        case 'hidden':
                                if(f.value==''){cf_adderr(f)}
                        break;
                        case 'textarea':
                                if(f.value==''){cf_adderr(f)}
                        break;
                        case 'checkbox':
                                if(!f.checked){cf_adderr(f)}
                        break;
                        case 'select-one':
                                if(!f.selectedIndex && f.selectedIndex==0){cf_adderr(f)}
                        break;

                }
        }
        if (!document.getElementById(errorID))
                eval(ajaxFunction)();
        //return !document.getElementById(errorID);

        /* Tool methods */
        function cf_adderr(o)
        {
                // create image, add to and colourise the error fields
                //var errorIndicator=document.createElement('img');
                //errorIndicator.alt=errorAlt;
                //errorIndicator.src=errorImg;
                //errorIndicator.title=errorTitle;
                o.className=errorClass;
                //o.parentNode.insertBefore(errorIndicator,o);

        // Check if there is no error message
                if(!document.getElementById(errorID))
                {
                // create errormessage and insert before submit button
                        var em=document.createElement('div');
                        em.id=errorID;
                        var newp=document.createElement('p');
                        newp.appendChild(document.createTextNode(errorMsg))
                        em.appendChild(newp);
/* added for linked list */
                        var newul=document.createElement('ul');
                        em.appendChild(newul);
/* end added for linked list */
                        // find the submit button
                        /*for(var i=0;i<of.getElementsByTagName('input').length;i++)
                        {
                                if(/submit/i.test(of.getElementsByTagName('input')[i].type))
                                {
                                        var sb=of.getElementsByTagName('input')[i];
                                        break;
                                }
                        }
                        if(sb)
                        {
                                sb.parentNode.insertBefore(em,sb);
                        }       */
                        var sb = document.getElementById(element);
                        sb.parentNode.insertBefore(em,sb);
                }
/* added for linked list */
                var em=document.getElementById(errorID).getElementsByTagName('ul')[0];
                var newli=document.createElement('li');
                var newa=document.createElement('a');
                for(var i=0;i<of.getElementsByTagName('label').length;i++)
                {
                        if(of.getElementsByTagName('label')[i].htmlFor==o.id)
                        {
                                var txt=of.getElementsByTagName('label')[i].firstChild.nodeValue;
                                break;
                        }
                }

                newa.appendChild(document.createTextNode(txt));
                newa.href='#'+f.id;
                newa.onclick=function()
                {
                        var loc=this.href.match(/#(\w.+)/)[1];
                        document.getElementById(loc).focus();
                        return false;
                }
                newli.appendChild(newa);
                em.appendChild(newli);
/* end added for linked list */
        }
        function cf_isEmailAddr(str)
        {
                return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
        }
}