js 上下左右键控制焦点(示例代码)

如下所示：

//begin---------------上下左右键控制
if('${iscontrol_mchntid}'.indexOf('${mchntid}')!=-1){
var texts = new Array();
//设置为focus所在的location
var x = 2;
var y = 3;
var maxx = 0;
var maxy = 0;
window.onload=function(){
var inputs = $("[location]");
for(var i = 0; i < inputs.length; i++){
texts.push(inputs[i]);
}
for(var i = 0; i < texts.length; i++){
texts[i].onfocus = new Function("setCurrent('" + texts[i].getAttribute("location") + "')");
var crtx = parseInt(texts[i].getAttribute("location").split(",")[0]);
var crty = parseInt(texts[i].getAttribute("location").split(",")[1]);
maxx = maxx < crtx ? crtx : maxx;
maxy = maxy < crty ? crty : maxy;
texts[i].onkeydown = function(e){
e = e || window.event;
switch(e.keyCode){
case 38:setPosition(x,y,38);break;// 上
case 40:setPosition(x,y,40);break;// 下
case 37:setPosition(x,y,37);break;// 左
case 39:setPosition(x,y,39);break;// 右
case 45:setPosition(x,y,45);break; // Insert键/返回键 在输入框里是删除且输入库有值时是删除 其他为返回上一页
default:return true;
}
}; 
}
};
function setPosition(x,y,keyCode){
//此处加入动态改变位置的逻辑----begin 
//上下时，只改动y坐标，x坐标自动改变
//左右时，只改动x坐标，y坐标自动改变
if(keyCode == '38' && x == '3'){
if(y=='3'||y=='4'||y=='5'||y=='6'||y=='7'||y=='8'){
y='3';
}
}
if(keyCode == '40' && x == '4'){
if(y=='3'||y=='4'||y=='5'||y=='6'||y=='7'||y=='8'){
y='3';
}
}
//此处加入动态改变位置的逻辑----end
if(keyCode == '38'){
x = --x; 
}
if(keyCode == '40'){
x = ++x; 
}
if(keyCode == '37'){
y = --y; 
}
if(keyCode == '39'){
y = ++y; 
}
movePosition(x,y,keyCode);
}
function movePosition(x1,y1,keyCode){
if(keyCode == '45'){
//光标所在的对象是input时
var st = x1+","+y1;
if($("input[location='"+st+"']").attr("type")=="text"){
var oldval = $("input[location='"+st+"']").val();
var newval = oldval.substring(0,oldval.length-1);
$("input[location='"+st+"']").val(newval);
return false;
}else{
history.go(-1); 
return false;
}
}
x1 = x1 > maxx ? 1 : x1;
y1 = y1 > maxy ? 1 : y1;
x1 = x1 < 1 ? maxx : x1;
y1 = y1 < 1 ? maxy : y1;
var j = 0;
for(; j < texts.length; j++){
if(texts[j].getAttribute("location") == x1 + "," + y1){ 
texts[j].focus();
break;
}
} 
if(j == texts.length){
switch(keyCode){
case 38:movePosition(--x1,y1,keyCode);break;// 上
case 40:movePosition(++x1,y1,keyCode);break;// 下
case 37:movePosition(x1,--y1,keyCode);break;// 左
case 39:movePosition(x1,++y1,keyCode);break;// 右
}
}
} 
function setCurrent(location){
x = location.split(",")[0];
y = location.split(",")[1];
}
}
//end---------------上下左右键控制