已知函数ym1x:为什么这段脚本语言读不来！

<SCRIPT>
function checkform(theform)
{
var letters = "abcdefghijklmnopqrstuvwxyz_0123456789" +
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
var letter = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

var allword = letters + "~!@#$%^&*()+|/?;:'[{]}`"
var errletter = ""

function CheckIfEnglish1( String )
{
var Letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890-";
var i;
var c;
if(String.charAt( 0 )=='-')
return false;
if( String.charAt( String.length - 1 ) == '-' )
return false;
for( i = 0; i < String.length; i ++ )
{
c = String.charAt( i );
if (Letters.indexOf( c ) < 0)
return false;
}
return true;
}

if(theform.user.value.length < 1)
{
alert("请输入用户名称！")
theform.user.focus()
return false
}

if(theform.user.value.length < 3)
{
alert("用户名称不能少于3个字符！")
theform.user.focus()
return false
}
return true
}
</SCRIPT>

<FORM method=post name=form1 id="form1" onsubmit="return checkform(this)" action="save.asp">
<p>
<input name="yonghuming" type="text" id="yonghuming" >
用户名 </p>
<p>
<input name="password" type="password" id="password">
密码 </p>
<p>
<input name="repassword" type="password" id="repassword">
密码确认</p>
<p>
<input name="xinxiang" type="text" id="xinxiang">
信箱</p>
<p>
<input name="sex" type="radio" value="1" >
男
<input type="radio" name="sex" value="2">
女 </p>
<p>
<input type="submit" name="Submit" value="提交">
</p>
</form>

</body>
</html>