function validateEmail(){
  regularExpression = /^[^\s]+@[^\s]+\.[^\s]{2,3}$/;
  var obj=document.getElementById('chkremail');
  var useremail=document.getElementById('useremail');

  if(useremail.value.length==0){
    obj.innerHTML='&nbsp;<img src=images/login_join_images/member_dot4.gif width=14 height=14 /><span class=text24> 請填信箱！</span>';
    window.status='請填信箱'; return key_email=false;
  }
  else if (!regularExpression.test(useremail.value)){
    obj.innerHTML='&nbsp;<img src=images/login_join_images/member_dot4.gif width=14 height=14 /><span class=text24> 無效信箱！</span>';
    window.status='無效信箱'; return key_email=false;
  }
  else{
    obj.innerHTML='&nbsp;<img src=images/login_join_images/member_dot3.gif width=14 height=14 /><span class=text25> 可用信箱！</span>';
    window.status='可用信箱'; return key_email=true;
  }
}

function replaceString(){
document.getElementById('useremail').value=document.getElementById('useremail').value.replace(/[\s!\\+=\-\[\]#$%^&*()|}{"':;?/><]/g,"");
}