John Drake

I wrote this Javascript code for fun!

It uses the browser's cookies system to save an easy-to-use to-do list's items. I don't use it myself, but my girlfriend integrated it into her desktop and uses it every day!

Code:

//LOADTODOLIST()
//Returns the part of the cookie where the data is stored
function loadToDoList()
{
	var index = document.cookie.indexOf("todo=");
	if (index == -1)
	{
		return "";
	}
	var start = document.cookie.indexOf("=", index) + 1;
	var end = document.cookie.indexOf(";", index);
	if (end == -1)
	{
		end = document.cookie.length;
	}
	if (start == 0 || start > end)
	{
		return "";
	}
	return document.cookie.substring(start, end);
}

//SAVETODOLIST()
//Saves the todo list (string input variable) to the part of the cookie where the data should be stored
//This is effectively the inverse of loadToDoList()
function saveToDoList(list)
{
	document.cookie = "todo=" + list + "; expires=Monday, 04-Apr-2010 05:00:00 GMT";
}

//GETTODOITEM
//Given an index to an item in the todo list, this function parses it out of the cookie's data from loadToDoList();
function getToDoItem(index)
{
	todolist = loadToDoList();
	var subindex = todolist.indexOf("<" + index + "|");
	var start = subindex;
	var end = todolist.indexOf(">", subindex) + 1;
	var temp = todolist.substring(start, end);
	return temp;
}

//GETTEXTFROMTODOITEM()
//From a todo list item acquired by calling getToDoItem(), this function parses the part to display on the list itself
function getTextFromToDoItem(todoitem)
{
	var offset = todoitem.indexOf("|");
	var start = offset + 3;
	var end = todoitem.indexOf(">");
	var temp = todoitem.substring(start, end);
	return temp;
}

//GETCHECKEDFROMTODOITEM()
//From a todo list item acquired by calling getToDoItem(), this function parses the state of the checkbox
function getCheckedFromToDoItem(todoitem)
{
	var start = todoitem.indexOf("|") + 1;
	var end = start + 1;
	var temp = todoitem.substring(start, end);
	return eval(temp);
}

//ASSEMBLEADDITEMFORM()
//This function returns HTML code for the "Add New ToDo List Item" form
//It needs to be generated here to incorporate information on how many items there are (and thus which index to add the new one under)
function assembleAddItemForm(index)
{
	return "<form name=\"additemform\" action=\"javascript:setToDoItem(" + (index + 1) + ", 0, document.additemform.newitemtext.value);\"><input type=\"text\" name=\"newitemtext\" value=\"Enter New Item Text Here\" size=32 onClick=\"document.additemform.newitemtext.value='';\"><br><input type=\"submit\" value=\"Add New To Do List Item\"></form>";
}

//ASSEMBLETODOLIST()
//This function uses most of the others to actually put together the todo list
function assembleToDoList()
{
	temp = "";
	temp += "<span id=\"todo\">To Do:</span>    <span id=\"redx\" title=\"Click here to clear the entire list!\" onClick=\"saveToDoList('');location.reload();\">X</span><form>";
	var todolist = loadToDoList();
	var index = 0;
	if (todolist == "")
	{
		return temp + "Nothing to do yet!<p></form>" + assembleAddItemForm(index);
	}
	var subindex = 0;
	var atend = 0;
	while (atend == 0)
	{
		index += 1;
		subindex = todolist.indexOf("<" + index + "|");
		if (subindex != -1)
		{
			var todoitem = getToDoItem(index);
			var checked = getCheckedFromToDoItem(todoitem);
			if (checked == 1)
			{
				var notchecked = 0;
			}
			else
			{
				var notchecked = 1;
			}
			var text = getTextFromToDoItem(todoitem);
			temp += "<input type=\"checkbox\" onClick=\"setToDoItem(" + index + ", " + notchecked + ", '" + text + "');\" ";
			if (checked == 1)
			{
				temp += "checked";
			}
			temp += ">" + dirty(text) + "  <span id=\"redx\" title=\"Click here to clear this list item!\" onClick=\"clearToDoItem(" + index + ");\">X</span><br>";
			var test = todolist.indexOf(">", subindex);
			if ((test + 2) > todolist.length)
			{
				atend = 1;
			}
		}
	}
	temp += "</form>" + assembleAddItemForm(index);
	return temp;
}

//CLEAN()
//This function takes a string of text that possibly has characters in it which the other ToDo List code uses as delimiters
//It removes these characters and replaces them with safe alternatives
//For some characters, a substitution is made which the dirty() function must modify before displaying the text to a user
function clean(text)
{
	if (text == "")
		return "";

var split = new Array();
//	alert(split.length);
//	alert("x" + text + "x");
	split = text.split("<");
	text = "";
//	alert("x" + split[0] + "x" + split[1] + "x");
//	alert(split.length);
	for (var i = 0; i < split.length - 1; i++)
	{
//		alert(split[i]);
		text += split[i] + "<";
	}
	if (split.length != 0)
		text += split[split.length - 1];
//	alert("x:" + text + ":x");

split = text.split(">");
	text = "";
	for (var i = 0; i < split.length - 1; i++)
	{
		text += split[i] + ">";
	}
	if (split.length != 0)
		text += split[split.length - 1];

split = text.split("|");
	text = "";
	for (var i = 0; i < split.length - 1; i++)
	{
		text += split[i] + "|";
	}
	if (split.length != 0)
		text += split[split.length - 1];

split = text.split(";");
	text = "";
	for (var i = 0; i < split.length - 1; i++)
	{
		text += split[i] + "!)@(#*$&%^";
	}
	if (split.length != 0)
		text += split[split.length - 1];

return text;
}

//DIRTY()
//This function takes text cleaned by clean() and restores the correct characters to the text
function dirty(text)
{
	split = text.split("!)@(#*$&%^");
	text = "";
	for (var i = 0; i < split.length - 1; i++)
	{
		text += split[i] + ";";
	}
	if (split.length != 0)
		text += split[split.length - 1];
	
	return text;
}

//SETTODOITEM()
//This function replaces an item with new text and checked information
function setToDoItem(index, checked, text)
{
	text = clean(text);
	todolist = loadToDoList();
	var subindex = todolist.indexOf("<" + index + "|");
	if (subindex == -1)
	{
		var temp = todolist.substring(0, todolist.length);
	}
	else
	{
		var temp = "";
	}
	if (subindex != -1)
	{
		var start = 0;
		var end = subindex;
		temp += todolist.substring(start, end);
	}
	temp += "<" + index + "|" + checked + "|" + text + ">";
	if (subindex != -1)
	{
		start = todolist.indexOf(">", subindex) + 1;
		end = todolist.length;
		temp += todolist.substring(start, end);
	}
	saveToDoList(temp);
	if (text == "")
	{
		clearToDoItem(index);
	}
	location.reload();
}

//CLEARTODOITEM()
//This function erases an item from the list
function clearToDoItem(index)
{
	todolist = loadToDoList();
	var subindex = todolist.indexOf("<" + index + "|");
	var start = 0;
	var end = subindex;
	temp = todolist.substring(start, end);
	start = todolist.indexOf(">", subindex) + 1;
	end = todolist.length;
	temp += todolist.substring(start, end);
	saveToDoList(temp);
	location.reload();
}