/*

	see validate_test.js for an example


	SETUP FOR FORM VALIDATION
	
	1. include this script in your page
	2. add onsubmit="return validate('formname',validate_settings)" to every form you wish to validate
	3. create a validate_settings variable in the page to specify which things to check for


	AVAILABLE SUBFUNCTIONS
	
	not_blank -- make sure a field has something in it, or that a menu is set (the value of the "unset" option of menus should be -1 for this to work)
	not_blank_menu -- make sure one element of a popup menu is selected (preferred over not_blank for menus)
	not_blank_radio -- make sure one element of a radio button is selected
	not_blank_checkbox -- make sure one element of a checkbox is selected
	not_zero -- for numeric values, make sure the value is not zero
	no_letters -- require that a field contain no letters (punctuation is okay)
	no_numbers -- require that a field contain no numbers (punctuation is okay)
	no_punctuation -- require that a field contain no punctuation
	some_caps -- encourage proper capitalization
	allowed -- specify which characters are allowed in the field
			   allowed_1234\. allows only the numbers 1, 2, 3, 4 and a dot
			   (actually, Netscape doesn't like slashes, even when escaped -- can we work around this in a future version?)
	length -- check for a length range or list of possible lengths (counts letters and numbers only)
			  also counts the length of a checkbox array
			  length_6 requires 6 characters, length_1-12 requires between 1 and 12 characters, length_1|3|5 requires 1, 3, or 5 characters
	email_characters -- check for various requirements of a valid email address
	credit_card -- check for the proper lengths and required characters of each type of credit card (ignore punctuation)
		      	   this assumes a field named card_type is also present on the form
	taxexempt_format -- check if the value has a valid tax exempt ID number format (Exxxx-xxxx-xx)
	SSN_format -- check if the value has a valid social security number format (xxx-xx-xxxx)
	
	
	REGULAR EXPRESSION SYMBOLS USED IN THE SUBFUNCTIONS

	\w matches alphanumeric, including "_".
	\W matches non-alphanumeric (i.e., punctuation) 

	\b matches word boundaries
	\B matches non-boundaries 

	\s matches whitespace
	\S matches non-whitespace 

	\d matches numeric
	\D matches non-numeric 
	
	
	VERSION HISTORY
	
	01/19/02 - Initial development
	10/21/02 - Added not_blank_menu, not_blank_radio, and not_blank_checkbox subfunctions; made card type switch not case-sensitive; added a setting to allow card_type to be a popup menu or a radio button
	11/11/02 - Fixed get_checkbox_value and get_menu_value, added get_menu_text, tweaked focus on not_blank_menu to avoid errors
	
	TO DO - make length count checkbox arrays


*/


// offer a few site-wide settings

	var card_type_style = "menu"; // possible values are menu and radio


// parse the validate settings and trigger all the other functions

	function validate(form_name, validate_settings) {
		validate_report = "";
		field_name_focus = "";
		
		fields_count = validate_settings.length / 3;
		for (i=0; i<fields_count; i++) {
			field_name = validate_settings[i*3];
			field_label = validate_settings[(i*3)+1];
			field_settings = validate_settings[(i*3)+2];
						
			if (field_settings.indexOf("not_blank_menu") != -1) {
				field_value = get_menu_value(form_name, field_name);
			} else if (field_settings.indexOf("not_blank_radio") != -1) {
				field_value = get_radio_value(form_name, field_name);
			} else if (field_settings.indexOf("not_blank_checkbox") != -1) {
				field_value = get_checkbox_value(form_name, field_name);
			} else {
				eval("field_value = document."+form_name+"."+field_name+".value");
			}
																							
			// strip quotes from the field_value; is there any other way to keep the following lines from breaking?
			field_value = field_value.replace(/(["'])/g,"\\$1");
			
			field_settings = field_settings.replace(/,\s+/g,",");
			field_settings = field_settings.split(",");
			settings_count = field_settings.length;
						
			for (j=0; j<settings_count; j++) {
				function_name = field_settings[j];
				
				// don't bother checking if the field is blank (unless we're checking not_blank!)
				if ((function_name.indexOf("not_blank") != -1)||((field_value.replace(/\s/g,"") != "")&&(field_value.replace(/\s/g,"") != "-1"))) {

					if (function_name.indexOf("length_") == 0) {
						// do some special parsing for the length function
						length_settings = function_name.substr(7,function_name.length)
						eval("lengthx('"+field_value+"','"+length_settings+"')");
					} else if (function_name.indexOf("allowed_") == 0) {
						// do some special parsing for the allowed function
						allowed_characters = function_name.substr(8,function_name.length)
						eval("allowed('"+field_value+"','"+allowed_characters+"')");
					} else if (function_name.indexOf("credit_card") == 0) {
						// send the card_type value to the credit_card function
						//eval("card_type = document."+form_name+".card_type.options[document."+form_name+".card_type.selectedIndex].text");
						if (card_type_style == "menu") {
							card_type = get_menu_text(form_name, "card_type");
						} else {
							// for this to return user-friendly results, you need to set your card IDs to words rather than numbers;
							// this isn't a problem with menus because there you can have an ID (option.value) -and- a human-readable name (option.text)
							card_type = get_radio_value(form_name, "card_type");
						}
						eval("credit_card('"+field_value+"','"+card_type+"')");
					} else {
						eval(function_name+"('"+field_value+"')");
					}
				
				}
			}
		}
		
		if (validate_report == "") {
			return true;
		} else {
			alert(validate_report);
			if (field_name_focus) { eval("document."+form_name+"."+field_name_focus+".focus()"); }
			return false;
		}
	}
	

// make sure a field has something in it, or that a menu is set (the value of the "unset" option of menus should be -1 for this to work)

	function not_blank(field_value) {
		field_value = field_value.replace(/\s/g,"");
		if ((field_value == "")||(field_value == "-1")) { // we could take out the -1 but for backwards compatibility with popup menus
			validate_report += field_label + " needs a value\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// make sure one element of a popup menu is selected

	function not_blank_menu(field_value) {
		field_value = field_value.replace(/\s/g,"");
		if ((field_value == "")||(field_value == "-1")) {
			validate_report += field_label + " needs a value\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// make sure one element of a radio button is selected

	function not_blank_radio(field_value) {
		field_value = field_value.replace(/\s/g,"");
		if (field_value == "") {
			validate_report += field_label + " needs a value\n";
			if (! field_name_focus) { field_name_focus = field_name + "[0]"; }
		}
	}


// make sure one element of a checkbox is selected

	function not_blank_checkbox(field_value) {
		field_value = field_value.replace(/\s/g,"");
		if (field_value == "") {
			validate_report += field_label + " needs a value\n";
			if (! field_name_focus) { field_name_focus = field_name + "[0]"; }
		}
	}


// for numeric values, make sure the value is not zero
	
	function not_zero(field_value) {
		field_value = parseFloat(field_value);
		if (field_value == 0) {
			validate_report += field_label + " needs a value\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// require that a field contain no letters (punctuation is okay)

	function no_letters(field_value) {
		field_value_compare = field_value.replace(/[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ]/g,""); // remove all letters
		if (field_value.length != field_value_compare.length) {
			validate_report += field_label + " should only contain numbers\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// require that a field contain no numbers (punctuation is okay)

	function no_numbers(field_value) {
		field_value_compare = field_value.replace(/\d/g,""); // remove all numbers
		if (field_value.length != field_value_compare.length) {
			validate_report += field_label + " should not contain numbers\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// require that a field contain no punctuation

	function no_punctuation(field_value) {
		field_value_compare = field_value.replace(/\W/g,""); // remove all punctuation, except underscores
		field_value_compare = field_value.replace(/_/g,""); // remove underscores
		if (field_value.length != field_value_compare.length) {
			validate_report += field_label + " should not contain numbers\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// encourage proper capitalization

	function some_caps(field_value) {
		field_value_compare = field_value.replace(/[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ]/g,"");
		if (field_value_compare.length < field_value.length) { // don't bother checking if there aren't any letters
			field_value_compare = field_value.toLowerCase(); // change to all lowercase
			if (field_value == field_value_compare) {
				validate_report += "Please use normal capitalization in "+field_label+" and elsewhere\n";
				if (! field_name_focus) { field_name_focus = field_name; }
			}
		}
	}


// specify which characters are allowed in a field
// allowed_1234\. allows only the numbers 1, 2, 3, 4 and a dot

	function allowed(field_value,allowed_characters) {
		eval("field_value = field_value.replace(/["+allowed_characters+"]/g,'');")
		if (field_value != "") {
			validate_report += field_label + " can't contain the characters '" + field_value + "'\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// check for a length range or list of possible lengths (counts letters and numbers only)
// also counts the length of a checkbox array
// length_6 requires 6 characters, length_1-12 requires between 1 and 12 characters, length_1|3|5 requires 1, 3, or 5 characters

	function lengthx(field_value,length_settings) {
		field_value = field_value.replace(/\W/g,""); // ignore punctuation
		if (length_settings.indexOf("-") != -1) {
			length_settings = length_settings.split("-");
			min = parseInt(length_settings[0]);
			max = parseInt(length_settings[1]);
			if ((field_value.length < min)||(field_value.length > max)) {
				validate_report += field_label + " should be between "+min+" and "+max+" characters long\n";
				if (! field_name_focus) { field_name_focus = field_name; }
			}
		} else if (length_settings.indexOf("|") != -1) {
			length_settings = length_settings.split("|");
			success = 0;
			oks = "";
			for (k=0; k<length_settings.length; k++) {
				ok = parseInt(length_settings[k]);
				if (field_value.length == ok) {
					success = 1;
					break;
				}
				if (k < length_settings.length - 1) {
					if (length_settings.length > 2) {
						oks += ok + ", ";
					} else {
						oks += ok + " ";
					}
				} else {
					oks += "or " + ok;
				}
			}
			if (success == 0) {
				validate_report += field_label + " should be "+oks+" characters long\n";
				if (! field_name_focus) { field_name_focus = field_name; }
			}
		} else {
			ok = parseInt(length_settings)
			if (field_value.length != ok) {
				validate_report = field_label + " should be "+ok+" characters long\n";
				if (! field_name_focus) { field_name_focus = field_name; }
			}
		}
	}


// check for various requirements of a valid email address

	function email_characters(field_value) {
			
		// checks for legal characters (@-._aZ09), characters that can't start the address,
		// characters that can't be together, only one @ symbol, legal characters after the @ (aZ09.-)
		check_general = /[^@\-\.\w_]|^[_@\.\-]|[@\._\-]{2}|(@)[^@]*\1|@[\w\-.]{1,}_/;
		
		// checks for at least one a-Z or 0-9 between the @ and the .
		check_domain = /@[\w\-]{1,}\./;
		
		// checks for two-, three- or four- character TLD (e.g. .de, .com, .info)
		check_TLD = /\.[a-zA-Z]{2,4}$/;

		if (((field_value.search(check_general) != -1)||(field_value.search(check_domain)) == -1)||(field_value.search(check_TLD) == -1)) {
			validate_report += field_label + " does not contain a valid email address\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	
	}


// check for the proper lengths and required characters of each type of credit card (ignore punctuation)
// this assumes a field named card_type is also present on the form

	function credit_card(field_value,card_type) {
		if (card_type.indexOf("...") == -1) {
			field_value = field_value.replace(/[^\d]/g,"");  // remove all but numbers
			success = 1;
			switch (card_type.substr(0,3).toLowerCase()) {
				case "vis" :
					// Visa: 16 or 13 digits long, first digit is 4
					if (!((field_value.length == 16)||(field_value.length == 13))||!(parseInt(field_value.substr(0,1)) == 4)) {
						success = 0;
					}
					break;
				case "mas" :
					// Mastercard: 16 digits long, first digit is 5, second digit is between 1 and 5 inclusive
					if (!(field_value.length == 16)||!((parseInt(field_value.substr(0,1)) == 5)&&(parseInt(field_value.substr(1,1)) >= 1)&&(parseInt(field_value.substr(1,1)) <= 5))) {
						success = 0;
					}
					break;
				case "dis" :
					// Discover: 16 digits long, first four digits are 6011
					if (!(field_value.length == 16)||!(parseInt(field_value.substr(0,4)) == 6011)) {
						success = 0;
					}
					break;
				case "ame" :
					// American Express: 15 digits long, first digit is 3, second digit is 4 or 7
					if (!(field_value.length == 15)||!((parseInt(field_value.substr(0,1)) == 3)&&((parseInt(field_value.substr(1,1)) == 4)||(parseInt(field_value.substr(1,1)) == 7)))) {
						success = 0;
					}
					break;
				case "din" :
					// Diner's Club: 14 digits long, first digit is 3, second digit is 0, 6, or 8
					if (!(field_value.length == 14)||!((parseInt(field_value.substr(0,1)) == 3)&&((parseInt(field_value.substr(1,1)) == 0)||(parseInt(field_value.substr(1,1)) == 6)||(parseInt(field_value.substr(1,1)) == 8)))) {
						success = 0;
					}
					break;
				case "car" :
					// Carte Blanche: 14 digits long, first digit is 3, second digit is 0, 6, or 8
					if (!(field_value.length == 14)||!((parseInt(field_value.substr(0,1)) == 3)&&((parseInt(field_value.substr(1,1)) == 0)||(parseInt(field_value.substr(1,1)) == 6)||(parseInt(field_value.substr(1,1)) == 8)))) {
						success = 0;
					}
					break;
				case "enr" :
					// EnRoute: 15 digits long, first four digits are 2014 or 2149
					if (!(field_value.length == 15)||!((parseInt(field_value.substr(0,4)) == 2014)||(parseInt(field_value.substr(0,4)) == 2149))) {
						success = 0;
					}
					break;
				case "jcb" :
					// EnRoute: 16 digits long, first four digits are 3088, 3096, 3112, 3158, 3337, or 3528
					if (!(field_value.length == 16)||!((parseInt(field_value.substr(0,4)) == 3088)||(parseInt(field_value.substr(0,4)) == 3096)||(parseInt(field_value.substr(0,4)) == 3112)||(parseInt(field_value.substr(0,4)) == 3158)||(parseInt(field_value.substr(0,4)) == 3337)||(parseInt(field_value.substr(0,4)) == 3528))) {
						success = 0;
					}
					break;
				default : 
					validate_report += card_type + " is not a valid credit card type\n";
					break;
			}
			if (! success) {
				validate_report += field_label + " is not a valid "+card_type+" number\n";
				if (! field_name_focus) { field_name_focus = field_name; }
			}
		} else {
			validate_report += field_label + " needs an associated card type\n";
		}
	}


// check if the value has a valid tax exempt ID number format (Exxxx-xxxx-xx)

	function taxexempt_format(field_value) {
		field_value = field_value.replace(/E\d{4}-\d{4}-\d{2}/,"okay");
		if (field_value != "okay") {
			validate_report += field_label + " is not a valid tax exempt ID\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}


// check if the value has a valid social security number format (xxx-xx-xxxx)

	function SSN_format(field_value) {
		field_value = field_value.replace(/\d{3}-\d{2}-\d{4}/,"okay");
		if (field_value != "okay") {
			validate_report += field_label + " is not a valid SSN\n";
			if (! field_name_focus) { field_name_focus = field_name; }
		}
	}
	

// return the texts of the selected menu items

	function get_menu_text(form_name, field_name) {
		eval("this_element = document."+form_name+"."+field_name+".options");
		selected_texts = new Array();
		for (k=0; k<this_element.length; k++) {
			if (this_element[k].selected) {
				//selected_texts.push(this_element[k].text); // why doesn't this line work? ("object doesn't support...")
				selected_texts[selected_texts.length] = this_element[k].text;
			}
		}
		selected_texts = selected_texts.join(",");
		return selected_texts;
	}


// return the values of the selected menu items (not_blank works on some, but not all, browsers, so this is safer)

	function get_menu_value(form_name, field_name) {
		eval("this_element = document."+form_name+"."+field_name+".options");
		selected_values = new Array();
		for (k=0; k<this_element.length; k++) {
			if (this_element[k].selected) {
				//selected_values.push(this_element[k].value); // why doesn't this line work? ("object doesn't support...")
				selected_values[selected_values.length] = this_element[k].value;
			}
		}
		selected_values = selected_values.join(",");
		return selected_values;
	}


// return the value of the selected radio button

	function get_radio_value(form_name, field_name) {
		eval("this_element = document."+form_name+"."+field_name);
		for (k=0; k<this_element.length; k++) {
			if (this_element[k].checked) {
				selected_value = this_element[k].value;
				return selected_value;
			}
		}
		return "";
	}


// return the values of the selected checkboxes as a comma-delimited list

	function get_checkbox_value(form_name, field_name) {
		eval("this_element = document."+form_name+"."+field_name);
		selected_values = new Array();
		for (k=0; k<this_element.length; k++) {
			if (this_element[k].checked) {
				//selected_values.push(this_element[k].value); // why isn't this line working? ("object doesn't support...")
				selected_values[selected_values.length] = this_element[k].value;
			}
		}
		selected_values = selected_values.join(",");
		return selected_values;
	}


/*

	would this be a better way to format the validate_settings variable?
	
	validate_settings = "
		
		name: not_blank, letters_only;
		
		phone: not_blank, numbers_only;
		
		email: not_blank, email;
		
		card_number: not_blank, numbers_only;
		
	"

*/