问一个初学者性有关问题 _JavaScript

问一个菜鸟性问题
<html>
<head>
<title>Earnest Bank Web</title>
<script language="JavaScript">
function show()
{
var useID=i.value;
var usep=p.value;

var IDlength=useID.length;
var PWlength=usep.length;
if(IDlength>=8){
alert("ID不超过8个字符");
i.fouse();
}
else if(PWlength!=5)
{
alert("密码不能超过5个字符");
p.fouse();
}
}
</script>
</head>
<body>
<h1 align=center>Earnest Bank</h1>
<table align=center>
<caption>登录</caption>
<tr><td>ID</td><td><input type=text name=i></td></tr>
<tr><td>password</td><td><input type=password name=p></td></tr>
<tr align=center><td colspan=2><input type=button value="确定" onClick="show()"></td></tr>

当我把上面的大于号改为=号时，可以弹出，如果不改就弹不出来请问这是怎么会事

------解决方案--------------------

HTML code


html>
<head>
<title>Earnest   Bank   Web</title>
<script  type="text/javascript" language= "JavaScript"> 
function   show() 
{ 
var   useID=i.value; 
var   usep=p.value; 

var   IDlength=useID.length; 
var   PWlength=usep.length; 
if(IDlength>8){ 
alert( "ID不超过8个字符 "); 
i.fouse(); 
} 
else   if(PWlength>5) 
{ 
alert( "密码不能超过5个字符 "); 
p.fouse(); 
} 
} 
</script>
</head>
<body>
<h1   align=center> Earnest   Bank </h1>
<table   align=center>
<caption>
登录
</caption>
<tr>
  <td> ID </td>
  <td><input   type="text"   name="i">
  </td>
</tr>
<tr>
  <td> password </td>
  <td><input   type="password"   name="p">
  </td>
</tr>
<tr   align=center>
  <td   colspan=2><input   type="button" value= "确定" onClick="show()">
  </td>
</tr>

------解决方案--------------------
写错了把 正常没问题的

------解决方案--------------------
JScript code
<script   language= "JavaScript "> 
function   show() 
{ 
var useID=document.getElementById("i"); 
var usep=document.getElementById("p"); 

if(useID.length>=8){ 
alert( "ID不超过8个字符 "); 
useID.focus(); 
} 
else  if(usep.length>=5) 
{ 
alert( "密码不能超过5个字符 "); 
usep.focus();
} 
} 
</script>