<!-- validation for Telephone number: start -->

var digits = "0123456789";
var TelephoneNumberDelimiters = "()- .";
var validWorldTelephoneChars = TelephoneNumberDelimiters + "+";
var minDigitsInITelephoneNumber = 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 = "";
    for (i = 0; i < s.length; i++)
    {
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function checkInternationalTelephone(strTelephone){
s=stripCharsInBag(strTelephone,validWorldTelephoneChars);
return (isInteger(s) && s.length >= minDigitsInITelephoneNumber);
}

<!-- validation Telephone: end -->

<!-- validation email: start -->

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 ID")
		   return false
		}

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

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

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

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

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

		 if (str.indexOf(" ")!=-1){
		    alert("Please enter a valid E-mail ID")
		    return false
		 }

	}

<!-- validation email: end -->


<!-- validation string length: start -->

function lenCheck(st,nam)
{
    if(st.length < 2) {
       alert("Please enter your complete " + nam);
       return false;
    }
}


function NoInteger(m, nam)
{   var i;
    for (i = 0; i < m.length; i++)
    {
        var c = m.charAt(i);
        if(c==" ")
        {
        }
        else
	    {
			if (((c >= 0) || (c < 9)))
			{
			  alert("In " + nam + ", please enter letters only");
			  return false;
			}
	    }
    }
}


var illegalChars = /[A-Za-z]/;
function illegalcharacter(m, nam)
{   var i;
    for (i = 0; i < m.length; i++)
    {
        var ch = m.charAt(i);
			if (illegalChars.test(ch) || ch=="'" || ch=="-" || ch==" " || isInteger(ch) || ch=="," || ch==".")
			{}
			else
			{
			  alert("Please do not use special characters in " + nam);
			  return false;
			}
    }

}


function trimString (str) {
  while (str.charAt(0) == ' ')
    str = str.substring(1);
  while (str.charAt(str.length - 1) == ' ')
    str = str.substring(0, str.length - 1);
  return str;
}

<!-- validation string length: end -->

function ValidateForm(){
  		var First_Name=document.request_form.elements[0].value;
		First_Name = trimString(First_Name);

		if(First_Name=="")
		{
		  alert("Please enter your First Name");
		  document.request_form.elements[0].focus();
		  return false;
		}
		if(NoInteger(First_Name, "First Name")==false)
		{
		  document.request_form.elements[0].focus();
		  return false;
		}
		if(illegalcharacter(First_Name, "First Name")==false)
		{
		  document.request_form.elements[0].focus();
		  return false;
		}


		var Last_Name=document.request_form.elements[1].value;
		Last_Name = trimString(Last_Name);

		if(Last_Name=="")
		{
		  alert("Please enter your Last Name");
		  document.request_form.elements[1].focus();
		  return false;
		}
		if(lenCheck(Last_Name, "Last Name")==false)
		{
		  document.request_form.elements[1].focus();
		  return false;
		}
		if(NoInteger(Last_Name, "Last Name")==false)
		{
		  document.request_form.elements[1].focus();
		  return false;
		}
		if(illegalcharacter(Last_Name, "Last Name")==false)
		{
		  document.request_form.elements[1].focus();
		  return false;
		}


	var emailID=document.request_form.elements[2];

	if ((emailID.value==null)||(emailID.value=="")){
		alert("Please enter your Email ID");
		emailID.focus();
		return false;
	}
	if (echeck(emailID.value)==false){
		emailID.focus();
		return false;
	}

		var company=document.request_form.elements[3].value;
		company = trimString(company);

		if(company=="")
		{
		  alert("Please enter your Company Name");
		  document.request_form.elements[3].focus();
		  return false;
		}
		if(lenCheck(company, "Company Name")==false)
		{
		  document.request_form.elements[3].focus();
		  return false;
		}
		if(illegalcharacter(company, "Company Name")==false)
		{
		  document.request_form.elements[3].focus();
		  return false;
		}
	var Telephone=document.request_form.elements[4].value;
	if ((Telephone==null)||(Telephone=="")||(Telephone.length<10)){
		alert("Please enter your complete telephone number incuding area code");
        document.request_form.elements[4].focus();
		return false;
	}
	if (checkInternationalTelephone(Telephone)==false){
		alert("Please enter a Valid Telephone Number");
        document.request_form.elements[4].select();
        document.request_form.elements[4].focus();
		return false;
	}
	var shortdesc=document.request_form.elements[5].value;
	if(shortdesc=="")
	{
	alert("Please enter brief description about your application");	
	document.request_form.elements[5].focus();
		return false;
	}
	
	}

// -->