function clear_textbox()
{
if (document.text_form.u_input.value == " Enter Your Search Here ")
document.text_form.u_input.value = "";
} 

function emailCheck(emailStr) {

// "http://javascriptsource.com" adresinden alınmıştır.

var emailPat=/^(.+)@(.+)$/
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
var validChars="\[^\\s" + specialChars + "\]"
var quotedUser="(\"[^\"]*\")"
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
var atom=validChars + '+'
var word="(" + atom + "|" + quotedUser + ")"
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
  	alert("Please check your e-mail address!")
	return false
    
}
var user=matchArray[1]
var domain=matchArray[2]
if (user.match(userPat)==null) {

    alert("Please check your user name!")
    return false
    
}

var domainArray=domain.match(domainPat)
if (domainArray==null) {
	alert("Please check your address!")
    return false
}
var atomPat=new RegExp(atom,"g")
var domArr=domain.match(atomPat)
var len=domArr.length
if (domArr[domArr.length-1].length<2 || 
    domArr[domArr.length-1].length>4) {

   alert("Please check your address!")
   return false
}

if (len<2) {
   var errStr="Please check your address!"
   alert(errStr)
   return false
}
return true;
}