// JavaScript Document
<!-- 
function setTab(m,n){ 
 var tli=document.getElementById("menu"+m).getElementsByTagName("li"); 
 var mli=document.getElementById("main"+m).getElementsByTagName("ul"); 
 for(i=0;i<tli.length;i++){ 
  tli[i].className=i==n?"hover":""; 
  mli[i].style.display=i==n?"block":"none"; 
 } 
} 

//--> 
function isNumber()
      {
          var a=document.getElementById ("yusuan").value;  
          var name=document.getElementById ("name").value; 
          
          if(name=="")
          {
            alert("Name isn't empty");
             document.getElementById ("name").focus();
            return false;
          }       
           if (!chkemail(document.getElementById ("email").value)){
            alert("Please enter the correct Email!");
           document.getElementById ("email").focus();
            return false;
            }
          if(isNaN(a))
          {
             alert("RMB isn't number");
              document.getElementById ("yusuan").focus();
             return false;
          }
          return true;
      }
function chkemail(str)
{
    var chkstr =/([a-zA-Z0-9_\.])+@([a-zA-Z0-9-])+(\.[a-zA-Z0-9-]+)+/;
    var temp = str.match(chkstr);
    if ( temp != null && temp[0] == str )
    {
    return true;
    }
    else
    {
    return false;
    }
}