[英]Uncaught TypeError: Cannot read property 'getContext' of null
這是我的HTML代碼,顯示了畫布:
<canvas id="backgroundCanvas" width="550" height=600"></canvas>
<canvas id="playerCanvas" width="550" height=600"></canvas
<canvas id="enemiesCanvas" width="550" height=600"></canvas>
據說是在這里發生問題的地方:
game.contextBackground = document.getElementById("backgroundCanvas").getContext("2d"); // line 32
game.contextPlayer = document.getElementById("playerCanvas").getContext("2d"); // line 33
game.contextEnemies = document.getElementById("enemiesCanvas").getContext("2d"); // line 34
該錯誤在第34行顯示:
未捕獲的TypeError:無法讀取null的屬性'getContext'
任何幫助深表感謝 :)
HTML加載完成之前,您的JavaScript似乎正在運行。 如果可以使用jQuery,則將js放在其中;
$( document ).ready(function() {
// js goes in here.
});
因為尚未正確關閉playerCanvas
的畫布標記, playerCanvas
:
<canvas id="backgroundCanvas" width="550" height=600"></canvas>
<canvas id="playerCanvas" width="550" height=600"></canvas>
<canvas id="enemiesCanvas" width="550" height=600"></canvas>
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