/*
Form Error Checker
Usage:
<form onsubmit="return checkform(this);" enctype="multipart/form-data" action="form/processor/file" method="post">
<input type="hidden" name="required" id="required" value="name,email,security_code" />
*/
function checkform(of) { 
	if(!document.getElementById || !document.createTextNode){return;}
	if(!document.getElementById('required')){return;}

	var errorID='errormsg';
	var errorClass='text'
	var errorMsg='Please fix the fields marked with: '; // Alert Error message
	var errorImg='images/alert.gif'; // Path to alert image
	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='';
	}

	// 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 '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;
		}
	}

	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))
			
			// clone and insert the error image
			newp.appendChild(errorIndicator.cloneNode(true));
			em.appendChild(newp);

			// 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);
			}
		} 
  	}

	function cf_isEmailAddr(str) {
		return str.match(/^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/);
	}
}