JS AxajS проверка на существования

function validation()
{
 
if(document.form1.acct_username.value=="")
{
document.getElementById("acct_username").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Enter your name</span>";
document.form1.acct_username.focus();
return false;
}
  if (! (/^([\(\)\.\_\-a-zA-Z0-9\[\]]{2,14})$/.test(document.form1.acct_username.value)) )
  {
  document.getElementById("acct_username").html=("<span class='ipsForm_required ipsType_smaller'>* Fill Login sender</span>");
  document.form1.acct_username.focus();
    return false;
}
 
 
 if ((document.form1.acct_username.value.length < 3) )
  {
  document.getElementById("acct_username").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Name should be more than 3 letters</span>";
  document.form1.acct_username.focus();
    return false;
  }
if(document.form1.acct_email.value=="")
  {
  document.getElementById("acct_email").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Fill E-mail sender</span>";
  document.form1.acct_email.focus();
    return false;
  }
  
 
 
  if (! (/^\w+[-_\.]*\w+@\w+-?\w+\.[a-z]{2,4}$/.test(document.form1.acct_email.value)) )
  {
  document.getElementById("acct_email").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Please enter a valid address</span>";
  document.form1.acct_email.focus();
    return false;
  }      
 
 
 
 
if(document.form1.chk.value=="")
{
document.getElementById("error").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Enter Captcha!</span>";
document.form1.chk.focus();
return false;
}
 
 
if(document.form1.ran.value!=document.form1.chk.value)
{
document.getElementById("error").innerHTML="<span class='ipsForm_required ipsType_smaller'>* Captcha Not Matched!</span>";
document.form1.chk.focus();
return false;
}
 
else
var check = document.getElementById("check");
check.onclick = function() {
    var old = this.innerText,
        that = this;
    this.innerText = "?????????..."
    this.disabled = true
 
    // colback function
    setTimeout(function() {
        that.innerText = old;
        that.disabled = false
    }, 10000)
}
 
 return true;
}