function moveCharacterdirection var character = $#character; var currentPosition = characterposition; var newPosition = ; switchdirection case left newPosition = top currentPositiontop

为了防止角色移动到屏幕外面，需要在移动角色的函数中添加边界检查的代码。可以在移动角色之前，检查新位置是否超出了屏幕边界，如果超出了，则不执行移动操作。

下面是一个示例代码，用于限制角色在屏幕内移动：

function moveCharacter(direction){ var character = $('#character'); var currentPosition = character.position(); var newPosition = {}; switch(direction){ case 'left': newPosition = {top: currentPosition.top, left: currentPosition.left - 50}; character.css('background-image', 'url(' + (isTransformed ? 'img/playerbig_left.gif' : 'img/player_left.gif') + ')'); break; case 'right': newPosition = {top: currentPosition.top, left: currentPosition.left + 50}; character.css('background-image', 'url(' + (isTransformed ? 'img/playerbig_right.gif' : 'img/player_right.gif') + ')'); break; case 'up': newPosition = {top: currentPosition.top - 50, left: currentPosition.left}; character.css('background-image', 'url(' + (isTransformed ? 'img/player1_big.gif' : 'img/player1.gif') + ')'); break; case 'down': newPosition = {top: currentPosition.top + 50, left: currentPosition.left}; character.css('background-image', 'url(' + (isTransformed ? 'img/player1_big.gif' : 'img/player1.gif') + ')'); break; }

// 检查新位置是否超出屏幕边界
var screenWidth = $(window).width();
var screenHeight = $(window).height();
var characterWidth = character.width();
var characterHeight = character.height();
if(newPosition.left < 0 || newPosition.left > screenWidth - characterWidth || newPosition.top < 0 || newPosition.top > screenHeight - characterHeight){
    // 新位置超出屏幕边界，不执行移动操作
    return;
}

character.animate(newPosition, 200);
checkTreasure();

}