Js keys control focus of sample code

As follows:

//Begin -- up and down key control
if('${iscontrol_mchntid}'.indexOf('${mchntid}')!=-1){
var texts = new Array();
//Set it to the location of focus
var x = 2;
var y = 3;
var maxx = 0;
var maxy = 0;
window.onload=function(){
var inputs = $("[location]");
for(var i = 0; i < inputs.length; i++){
texts.push(inputs[i]);
}
for(var i = 0; i < texts.length; i++){
texts[i].onfocus = new Function("setCurrent('" + texts[i].getAttribute("location") + "')");
var crtx = parseInt(texts[i].getAttribute("location").split(",")[0]);
var crty = parseInt(texts[i].getAttribute("location").split(",")[1]);
maxx = maxx < crtx ? crtx : maxx;
maxy = maxy < crty ? crty : maxy;
texts[i].onkeydown = function(e){
e = e || window.event;
switch(e.keyCode){
case 38:setPosition(x,y,38);break;//  on 
case 40:setPosition(x,y,40);break;//  Under the 
case 37:setPosition(x,y,37);break;//  On the left 
case 39:setPosition(x,y,39);break;//  right 
case 45:setPosition(x,y,45);break; //The Insert key/return key is deleted in the input field and the input library has a value to delete the others to return to the previous page
default:return true;
}
}; 
}
};
function setPosition(x,y,keyCode){
//Add begin, the logic to dynamically change position
//Up and down, only change the y coordinate, the x coordinate changes automatically
//When left or right, only the x-coordinate is changed, and the y-coordinate is changed automatically
if(keyCode == '38' && x == '3'){
if(y=='3'||y=='4'||y=='5'||y=='6'||y=='7'||y=='8'){
y='3';
}
}
if(keyCode == '40' && x == '4'){
if(y=='3'||y=='4'||y=='5'||y=='6'||y=='7'||y=='8'){
y='3';
}
}
//Add the logic of dynamically changing position here --end
if(keyCode == '38'){
x = --x; 
}
if(keyCode == '40'){
x = ++x; 
}
if(keyCode == '37'){
y = --y; 
}
if(keyCode == '39'){
y = ++y; 
}
movePosition(x,y,keyCode);
}
function movePosition(x1,y1,keyCode){
if(keyCode == '45'){
//The object on which the cursor is located is input
var st = x1+","+y1;
if($("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;//  on 
case 40:movePosition(++x1,y1,keyCode);break;//  Under the 
case 37:movePosition(x1,--y1,keyCode);break;//  On the left 
case 39:movePosition(x1,++y1,keyCode);break;//  right 
}
}
} 
function setCurrent(location){
x = location.split(",")[0];
y = location.split(",")[1];
}
}
//End -- up, down, left and right key control