function externalLinks() {
	if (!document.getElementById) return;
	document.getElementById("basket").target = "paypal";
	if (document.getElementById("add")) {
		document.getElementById("add").target = "paypal";
	}
}

window.onload = function() {
	externalLinks();
}

function checkForm() {
	name = document.getElementById("name").value;
	email = document.getElementById("email").value;
	emailregex = /^([a-zA-Z0-9])+([\.a-zA-Z0-9_-])*@([a-zA-Z0-9])+(\.[a-zA-Z0-9_-]+)+$/;
	comments = document.getElementById("comments").value;
	if (comments == '') {
		alert ("You must enter some comments.");
		return false;
	} else if (!emailregex.test(email)) {
		alert ("Please enter a valid email address.");
		return false;
	} else {
		return true;
	}
}

function getElementsByClassName(needle) {
	var my_array = document.getElementsByTagName("*");
	var retvalue = new Array();
	var i;
	var j;
	for (i=0,j=0;i<my_array.length;i++) {
		var c = " " + my_array[i].className + " ";
		if (c.indexOf(" " + needle + " ") != -1) retvalue[j++] = my_array[i];
	}
	return retvalue;
}

function updatePrice(price,original) {
	var additional_pair = document.getElementById('os0');
	if (additional_pair.value != '' && additional_pair.value != 'None selected') {
		// An additional pair has been selected, update the hidden price field for PayPal
		document.getElementById('amount').value = price;
	} else {
		// Reset the price to original price for one pair
		document.getElementById('amount').value = original;
	}
}