function isNumberKey(evt)
      {
         var charCode = (evt.which) ? evt.which : event.keyCode
         if (charCode > 31 && (charCode < 48 || charCode > 57))
            return false;

         return true;
      }
       function Chk_Field()
   {
    var txtPhone1=document.getElementById (prefix+"txtPhone1");
    var txtPhone2=document.getElementById (prefix+"txtPhone2");
    var txtPhone3=document.getElementById (prefix+"txtPhone3");
  
 
     var txtfname=  document.getElementById (prefix+"txtfname");
    var txtlname=document.getElementById (prefix+"txtlname");
    var txtEmail=document.getElementById (prefix+"txtEmail");
  
 
  

    if(txtfname.value =="" ||txtfname.value==null)
    {
       alert("First Name field Can't be empty");
       txtfname .focus ();
       return false;
    }
      if(txtlname.value =="" ||txtlname.value==null)
    {
       alert("Last Name field Can't be empty");
       txtlname .focus ();
       return false;
    }
    if(txtEmail.value =="" ||txtEmail.value==null)
    {
       alert("Email field Can't be empty");
       txtEmail.focus ();
       return false;
    }
     else
    {
     var bool= echeck(txtEmail.value);
     if(bool==0)
     {
     alert("Invalid E-mail ID");
     txtEmail.value ="";     
       txtEmail.focus ();
       return false;
      }
    }
   
      if(txtPhone1.value =="" ||txtPhone1.value==null)
     {
       alert("Phone field Can't be empty");
      txtPhone1.focus ();
       return false;
        
     }
    
     if(txtPhone1.value !="" &&(txtPhone2.value ==""||txtPhone3.value ==""))
     {
       alert("Phone no is not valid!all three fields are complusory");
      txtPhone1.focus ();
       return false;
        
     }
      if(txtPhone2.value !="" &&(txtPhone1.value ==""||txtPhone3.value ==""))
     {
         alert("Phone no is not valid!all three fields are complusory");
     txtPhone1.focus ();
       return false;
     }
      if(txtPhone3.value !="" &&(txtPhone1.value ==""||txtPhone2.value ==""))
     {
        alert("Phone no is not valid!all three fields are complusory");
       txtPhone1.focus ();
       return false;
     }
     
    
   
  return true;
  }
   function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		  
		   return 0;
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   
		    
		   return 0;
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		   
		   return 0;
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    
		   return 0;
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		   
		   return 0;
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    
		   return 0;
		 }
		
		 if (str.indexOf(" ")!=-1){
		    
		   return 0;
		 }

 		 return 1;					
	}