Javascript CSS只绘制左边框和上边框，而忽略右边框和下边框

所以我有这个数组

[["1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1"],
    ["1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1"],
    ["1","1","0","0","0","0","0","0","0","0","0","0","0","0","0","0","0","0","0","1"],
    ["1","1","1","0","0","0","0","0","0","0","0","0","0","0","0","0","0","0","1","1"],
    ["1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","0","0","1","1"],
    ["1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1"],
    ["0","0","0","0","0","0","0","0","0","1","1","0","0","0","0","0","0","0","0","0"],
    ["0","0","0","0","0","0","0","0","0","1","1","0","0","0","0","0","0","0","0","0"],
    ["0","0","0","0","0","0","0","0","0","1","1","0","0","0","0","0","0","0","0","0"],
    ["0","0","0","0","0","0","0","0","1","1","1","1","0","0","0","0","0","0","0","0"],
    ["0","0","0","0","0","0","0","1","1","1","1","1","1","0","0","0","0","0","0","0"],
    ["1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1","1"]]

代表这张地图的

此函数将根据1相对于0的位置，为空白平铺绘制边框

function lagTile(color,a,b){
var div=document.createElement("div");
var size=32;
div.style.width=div.style.height=size+"px";
div.style.left=a*size+"px";
div.style.top=b*size+"px";
canvas.appendChild(div);
if(color.substr(color.length-3,color.length)=="png"){
    div.style.backgroundImage="url(map/"+color+")";
}else{
    div.style.backgroundColor=color;
}
if(b>0 && map[b-1][a]==1 && map[b][a]==0)
{
    div.style.borderTop="4px solid #630";
    div.innerHTML="Top ";
}
if(b<map.length-1 && map[b+1][a]==1 && map[b][a]==0)
{
    div.style.borderBottom="4px solid #630";
    div.innerHTML+="Bottom ";
}
if(a<map[b].length-1 && map[b][a+1]==1 && map[b][a]==0)
{
    div.style.borderRight="4px solid #630";
    div.innerHTML+="Right ";
}
if(a>0 && map[b][a-1]==1 && map[b][a]==0)
{
    div.style.borderLeft="4px solid #630";
    div.innerHTML+="Left ";
}

功能标签（颜色、a、b）{
var div=document.createElement（“div”）；
变量大小=32；
div.style.width=div.style.height=size+“px”；
div.style.left=a*尺寸+px；
div.style.top=b*大小+px；
canvas.appendChild（div）；
if（color.substr（color.length-3，color.length）=“png”）{
div.style.backgroundImage=“url（map/“+color+””）；
}否则{
div.style.backgroundColor=颜色；
}
如果（b>0&&map[b-1][a]==1&&map[b][a]==0）
{
div.style.borderTop=“4px solid#630”；
div.innerHTML=“Top”；
}
如果（b边框是尺寸之外的，则元素会变大，并与后面的元素重叠（在下方或右侧）。因此边框就在那里，就隐藏在它后面绘制的框下面。有关大小调整的工作原理，请参见。简而言之，框的总宽度是div的宽度+左边框大小+右边框大小

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您可以通过从div的大小中减去边框大小来解决这个问题（例如，当您添加4px的左边框时，您也可以从宽度中删除4px），或者通过在其样式中添加

框大小：边框框

。

这太棒了！！！：d为了您的理智，请选择

框大小：边框

选项