// JavaScript Document
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}


<!---Contact us Validation---->
function Form_Validator(theForm)
{

var digits = "0123456789";
var phoneNumberDelimiters = "()- ";
var validWorldPhoneChars = phoneNumberDelimiters + "+";
var minDigitsInIPhoneNumber = 10;

function isInteger(s)
{   var i;
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag)
{   var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function checkInternationalPhone(strPhone){
s=stripCharsInBag(strPhone,validWorldPhoneChars);
return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
}

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){
		   alert("Please enter a valid email.")
		   return (false);
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Please enter a valid email.")
		   return (false);
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Please enter a valid email.")
		    return (false);
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Please enter a valid email.")
		    return (false);
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Please enter a valid email.")
		    return (false);
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Please enter a valid email.")
		    return (false);
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Please enter a valid email.")
		    return (false);
		 }

 		 return true;
}


  if (theForm.name.value == "")
  {
     alert("Please enter your name.");
     theForm.name.focus();
     return (false);
  }

  if (theForm.position.value == "")
  {
     alert("Please enter your position name.");
     theForm.position.focus();
     return (false);
  }

var emailID=theForm.email;
	
if ((emailID.value==null)||(emailID.value=="")) {
  alert("Please enter your email address.");
  theForm.email.focus();
  return false;
}

if (echeck(emailID.value)==false) {
  emailID.value="";
  theForm.email.focus();
 return false;
}

  if (theForm.companyname.value == "")
  {
     alert("Please enter your Company Name.");
     theForm.companyname.focus();
     return (false);
  }

  return (true);
}
<!---//Contact us Validation---->