javascript - Having trouble clearing canvas element -

the problem i'm having lines not clearing canvas. not quite sure why. i've looked issue quite awhile. here's of code:

function handles creation of line segments

var ui= {        clear:function()     {         gsx.clearrect(0,0,window.gsw,window.gsh);     },     drawcharacterrays:function()     {         for(z=0;z<walljoints.length;z++)         {             originx=(gsw/2);             originy=(gsh/2);             gsx.strokestyle='#ff0000';             gsx.beginpath();             gsx.moveto(originx,originy);             gsx.lineto(walljoints[z][0],walljoints[z][1]);             gsx.closepath();             gsx.stroke();         }      } } 

and code show order @ functions called:

function engine() {        ui.clear();      gsx.fillstyle="#ffffff";     gsx.fillrect((gsw-characterw)-window.x,(gsh-characterh)-window.y,mapw,maph);      ui.drawmap(curlevel,     [1,1,0,0,0,0,0,1,0,1],     [1,1,0,0,0,0,0,1,0,1]);      ui.drawcharacterrays();     ui.drawcharacter();     ui.drawstaminabar();     ui.drawhealthbar(); } 

i'd happy drop more code if needed, warned... there's lot...

saved myself time , made functional version in fiddle here : http://jsfiddle.net/cav63