javascript - Game code breaking when setting variable -

this game code seems fine, it's not working:

//get canvas , context var canvas = document.getelementbyid('canvas'); var ctx = canvas.getcontext('2d');  //capture keypresses var keys = []; document.onkeydown = function (e) {keys[e.keycode] = true;}; document.onkeyup = function (e) {keys[e.keycode] = false;};  //set game variables var characters; characters.charlist = []; var player = {};  //character constructor function character (name, strength, speed, intelligence, reflexes, age, height, weight, weapon, usesmagic, magictype, armor, hair, eyes, skin, clothes, species, type, accessories) {         this.name = name;         this.strength = strength;     this.speed = speed;     this.intelligence = intelligence;     this.reflexes = reflexes;     this.age = age;     this.height = height;     this.weight = weight;     this.weapon = weapon;     this.usesmagic = usesmagic;     this.magictype = magictype;     this.armor = armor;     this.hair = hair;     this.eyes = eyes;     this.skin = skin;     this.clothes = clothes;     this.species = species;     this.type = type;     if (accessories) {             this.accessories = accessories;     }     characters.charlist[characters.charlist.length] = name; }  characters.xantar = new character('xantar', 1, 1, 1, 1, 1, 1, 1, 'sword', true, 'derp', [], 'hair brown\?', 'duh', 'foo', [], 'animale', 'wolf', []); alert(characters.xantar.weapon + '   ' + characters[0].type);  //activate mainloop , value pausing purposes var mainloopinterval = setinterval(mainloop, 5); //main game loop function mainloop(){  } 

the program seems stop at:

characters.charlist = []; 

i don't see problem here. here relevant html:

<canvas id='canvas' style='border:1px solid black;'>your browser not support canvas. please update browser.</canvas> 

note: running on jsfiddle. if me here, grateful. here link: https://jsfiddle.net/q6vdph1p/14/.

as noted before, need assign object characters variable before you'll able access properties in it.

just declaring var characters; assign value of undefined , trying access undefined.charlist , assign empty array fail.

a more proper, fail resistant, , readable way of declaring building empty data structure, so:

var characters = {     charlist: [] }; 

also, adding end of array more safe using array.push() indexing array.length, i.e.

characters.charlist.push(name); 

rather than

characters.charlist[characters.charlist.length] = name;