javascript - Why is my canvas blank except for in a corner? -

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i'm in process of learning javascript playing canvas, i've managed make grid of squares randomly generated color.

i decided make each squares color increase , decrease in intensity result small corner of grid being drawn, , color doesn't change. doing wrong?

online code here , paste bin here.

var canvas = document.getelementbyid('mycanvas'); var ctx = canvas.getcontext("2d");  ctx.clearrect(0, 0, canvas.width, canvas.height);  function square(x, y) {     this.x = x;     this.y = y;     this.sizex = 10;     this.sizey = 10;     this.colo = colo;      function colo() {         var r = math.floor(math.random() * (255 - 1) + 1);         var g = math.floor(math.random() * (255 - 1) + 1);         var b = math.floor(math.random() * (255 - 1) + 1);         var run = true;         var rup, gup, bup = true;         while (run) {              if (rup) {                 if (r == 255) {                     rup = false;                 } else if (r == 0) {                     rup = true;                 }                  r += 1;                 r.tostring();              } else if (!gup) {                 r -= 1;                 r.tostring();             }              if (gup) {                 if (g == 255) {                     gup = false;                 } else if (g == 0) {                     gup = true;                 }                 g += 1;                 g.tostring();              } else if (!gup) {                 g -= 1;                 g.tostring();             }              if (bup = true) {                 if (b == 255) {                     bup = false;                 } else if (b == 0) {                     bup = true;                 }                  b += 1;                 b.tostring();              } else if (!gup) {                 b -= 1;                 b.tostring();             }              ctx.clearrect(0, 0, canvas.width, canvas.height);             var col = "rgb(" + r + "," + g + "," + b + ")";              return col;             window.onfocus = function () {                 rup = true;             };             window.onblur = function () {                 isactive = false;             };             console.log("ran loop.")         }     }      ctx.fillstyle = colo();     ctx.fillrect(this.x, this.y, this.sizex, this.sizey); }  var squares = new array(); var p = 0; (var = 0; < 128; i++) {     (var j = 0; j < 72; j++) {         p = + j;         squares[p] = new square(i * 10, j * 10);     } }

your square() constructor this:

ctx.fillstyle = colo(); ctx.fillrect(this.x, this.y, this.sizex, this.sizey);

... colo(), among other things, this:

ctx.clearrect(0, 0, canvas.width, canvas.height);

so, clearing entire canvas before painting each rectangle.


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