function checkSpace(ctrl,ctrlname)
{
	if(ctrl == "undefined" || ctrl == null) 
	{
		alert(ctrlname + " Object Not Defined");
		return false;
	}
	var content;
	content = ctrl.value;
	
	//for space entered 		
	if(content.length > 0)
	{
		for(var i=0;i<content.length;i++)
		{
			if(content.charAt(i)!=String.fromCharCode(32))
			{
				return true;
			}
		}
		alert("Please Enter Valid " + ctrlname);
		ctrl.value=""
		ctrl.focus();	
		return false;
	}
	else
	{
		//for null 
		alert("Please Enter" + ctrlname);
		ctrl.focus();	
		return false;
	}
	return true;
}



//***************************************************************************
// Removes Leading and Trailing White Spaces
//***************************************************************************
function trim(txt) {
	if(txt == null || txt == "" || txt == "undefined") {
		return "";
	}
        var re = "\\s*";
        var re1 = new RegExp("^" + re);
        var re2 = new RegExp(re + "$");
        txt = txt.replace(re1,"");
        txt = txt.replace(re2,"");
        return txt;
}

//***************************************************************************
//Check if the Email is Valid.
// return email if valid,\
// false otherwise
//***************************************************************************
function validEmail(srcObj,objNamePassed) {
	if(srcObj == "undefined" || srcObj == null) {
		alert(objNamePassed + " Object Not Defined");
		return false;
	}
	var email = srcObj.value;
	var objName = objNamePassed;
	if(objName == "" || objName == null) {
		objName = "Email ID " + srcObj.name ;
	}
	email = trim(email);
	srcObj.value = email;
	var re = new RegExp("^\([\\w_\\-\\.]+\)\@\([\\w_\\-]\+\\.\)+\([\\w_]\+\)$");
	if(email.match(re)) {
		return email;
	}
	alert("'" + email + "' is not a Valid Email Id");
	srcObj.focus();
	return false;
}



//***************************************************************************
// Function for Checking Mandatory Fields are Entered
// INPUTS : Control Name and Field Name
// Here ctrl is the object and ctrlname is Name or Caption for that object
//***************************************************************************
function mandatory(ctrl,ctrlname)
{
    
	if(ctrl == "undefined" || ctrl == null) 
	{
		alert(ctrl + " Object Not Defined");
		return false;
	}
	if(ctrl.value=="")
	{
		alert("Please Enter " + ctrlname);
		ctrl.focus();
		return false;
	}
	else if(checkSpace(ctrl,ctrlname)==false)
	{
		return false;
	}
	return true;
}






//***************************************************************
// Check string containe only letters
//****************************************************************
function isAlphabet(obj, objName)
{
	var alphaExp = /^[a-zA-Z]+$/;
	if(obj.value.match(alphaExp)){
		return true;
	}else{
		alert("You must enter Alphabets in "+ objName + " field");
		obj.focus();
		return false;
	}
}

//***************************************************************
// Check string contain numbers and letters only
//****************************************************************
function isAlphanumeric(obj, objName)
{
	var alphaExp = /^[0-9a-zA-Z]+$/;
	if(obj.value.match(alphaExp)){
		return true;
	}else{
		alert("You can enter only  Alphabets or numbers in "+ objName +" field");
		obj.focus();
		return false;
	}
}




//**************************************************************************
//Comparing Indian Date with Current Date
//**************************************************************************
function compareUSWithCurrentDate(today,todate,toname)
{

	if (validUSDate(todate,toname) == false)
	{
		return false;
	} 
	//obtain month,day and year of date2
	var mdate = todate.value;	
	var pos1 = mdate.indexOf("/");
	var newdate = mdate.substr(pos1+1);
	var pos2 = newdate.indexOf("/");
	var mval2= mdate.substr(0,pos1);
	var dval2 = newdate.substr(0,pos2);
	var yval2 = newdate.substr(pos2+1);
		
	//obtain month,day and year of current date
	var mdate = today;
	var pos1 = mdate.indexOf("/");
	var newdate = mdate.substr(pos1+1);
	var pos2 = newdate.indexOf("/");
	var mval3= mdate.substr(0,pos1);
	var dval3= newdate.substr(0,pos2);
	var yval3= newdate.substr(pos2+1);
	var date1=mval2 + "/" + dval2 + "/" + yval2;
	var today1=mval3 + "/" + dval3 + "/" + yval3;

	
	date1=new Date(date1);
	today1=new Date(today1);
	

	if(date1 >today1) 
	{ 
		alert(toname + " should be lesser than or equal to current date");
		todate.focus();
		return false; 
			
	} 
	return true;
}
<!------------website Url---------->

function validUrl(srcObj,objNamePassed) {
	if(srcObj == "undefined" || srcObj == null) {
		alert(objNamePassed + " Object Not Defined");
		return false;
	}
	var email = srcObj.value;
	var objName = objNamePassed;
	if(objName == "" || objName == null) {
		objName = "Email ID " + srcObj.name;
	}
	email = trim(email);
	srcObj.value = email;
	var re = new RegExp("^\([\\w_\\-\\.]+\)\.\([\\w_\\-]\+\\.\)+\([\\w_]\+\)$");
	if(email.match(re)) {
		return email;
	}
	alert("'" + email + "' is not a Valid Value for " + objName);
	
	return false;
}

function isPhoneNumber(obj,objname)
{
  var pno
  if(ParseUSNumber(obj.value)==false)
  {
	alert(" Please enter a valid Number (e.g. XXX-XXX-XXXX)");
	obj.focus();
	return false; 
  }
 // pno=ParseUSNumber(obj.value)
 // obj.value=pno
  var re = /^\d{3}-\d{3}-\d{4}$/;
  if (re.test(obj.value) != true)
  {
  		alert(" Please enter a valid Number (e.g. XXX-XXX-XXXX)");
		obj.focus();
		return false; 
  }
  return true;
}

function ParseUSNumber(PhoneNumberInitialString)
  {
  
    var FmtStr="";
    var index = 0;
    var LimitCheck;
 	var re = /^1\-\d{3}-\d{3}-\d{4}$/;
	 if (PhoneNumberInitialString!="")
 	 { 
	  if (re.test(PhoneNumberInitialString) != true)
	  {
		LimitCheck = PhoneNumberInitialString.length;
		while (index != LimitCheck)
		{
			if (isNaN(parseInt(PhoneNumberInitialString.charAt(index))))
			  { }
			else
			  { FmtStr = FmtStr + PhoneNumberInitialString.charAt(index); }
			index = index + 1;
		}
    	if (FmtStr.length == 10)
		{
			FmtStr = "1-" + FmtStr.substring(0,3) + "-" + FmtStr.substring(3,6) + "-" + FmtStr.substring(6,10);
		}
    	else
      	{
			FmtStr=PhoneNumberInitialString;
			//alert("Please enter a valid Phone Number (e.g. 1-XXX-XXX-XXXX)");
			obj=document.getElementById("txthomephone");
			obj.focus();
      	}
	    return FmtStr;
	  }
	  else
	  {
	  	return PhoneNumberInitialString;
	  }
	  
	 }
	 else
	 {
	  return PhoneNumberInitialString;
	 }
	 return true;
  }


function validateeventdate(month, date, year)
{   
    month= trim(month);
    date=trim(date);
    year=trim(year);
    
    if((month=="Jan" || month == "Mar" || month =="May" || month == "Jul" || month == "Aug" || month == "Oct" || month =="Dec") && date > '0' && date <= '31') 
	    {return true;}
    else if((month=="Apr" || month == "Jun" || month =="Sep" || month == "Nov") && date > '0' && date <= 30)
	    { return true;}
    else if( year % 4 ==0 && month =="Feb" && date > '0' && date <= 29)
	    {return true;}
    else if (year % 4 !=0 && month =="Feb" && date > '0' && date <= 28)
        { return true;}
}

//***************************************************************************
//Check if the Email is Valid.
// return email if valid,\
// false otherwise
//***************************************************************************
function validMultipleEmail(srcObj,objNamePassed,strEmail) {
	var email = strEmail;
	var objName = objNamePassed;
	if(objName == "" || objName == null) {
		objName = "Email ID " + srcObj.name ;
	}
	email = trim(email);
	//srcObj.value = email;
	var re = new RegExp("^\([\\w_\\-\\.]+\)\@\([\\w_\\-]\+\\.\)+\([\\w_]\+\)$");
	if(email.match(re)) {
		return email;
	}
	alert("'" + email + "' is not a Valid Email Id");
	srcObj.focus();
	return false;
}



//***************************************************************
// Check string contain  letters only
//****************************************************************
function alpha(obj, objName)
{
	var alphaExp = /^[a-zA-Z]+$/;
	if(obj.value.match(alphaExp)){
		return true;
	}else{
		alert("You must enter letters in "+ objName +" field");
		obj.focus();
		return false;
	}
}


//***************************************************************
// Check string contain numbers only
//****************************************************************
function numb(obj, objName)
{
	var numbExp = /^[0-9]+$/;
	if(obj.value.match(numbExp)){
		return true;
	}else{
		alert("You must enter only integer in "+ objName +" field");
		obj.focus();
		return false;
	}
}


//****************************************************************8
// Function for RadioButton Validation
//**************************************************************88
function radio_button_checker(ctrl,ctrlname)
{
// set var radio_choice to false
var radio_choice = false;

// Loop from zero to the one minus the number of radio button selections
for (var counter = 0; counter < ctrl.length; counter++)
{
// If a radio button has been selected it will return true
// (If not it will return false)
if (ctrl[counter].checked)
radio_choice = true; 
}

if (!radio_choice)
{
// If there were no selections made display an alert box 
alert("Please select an option.")
return (false);
}
}

//****************************************************************8
// Function for Checkbox  Validation
//**************************************************************88
function checkbox(ctrl,ctrlname)
{
var radio_choice = false;

// Loop from zero to the 
// (If not it will return false)
for (var counter = 0; counter < ctrl.length; counter++)
{
// If a radio button has been selected it will return true
// (If not it will return false)
if (ctrl[counter].checked)
radio_choice = true; 
}
 
if (!radio_choice)
{
// If there were no selections made display an alert box 
alert("Please select an option.")
return (false);
}
}


//***************************************************************
// Check string contain  Password with  first 2letters numbers and last 4 letters alphabets
//****************************************************************
function pass(obj, objName)
{
	var alphaExp = /^[0-9]{2}[a-zA-Z]{4}$/;
	if(obj.value.match(alphaExp)){
		return true;
	}else{
		alert("You must enter first 2 numbers and last 4 alphabets  in "+ objName +" field");
		obj.focus();
		return false;
	}
}



//***************************************************************
// Check string contain Phone number in XXX-XXX-XXXX format only
//****************************************************************
function num(obj, objName)
{
	var numbExp = /^[ ]*[(]{0,1}[ ]*[0-9]{3,3}[ ]*[)]{0,1}[-]{0,1}[ ]*[0-9]{3,3}[ ]*[-]{0,1}[ ]*[0-9]{4,4}[ ]*$/;
	if(obj.value.match(numbExp)){
		return true;
	}else{
		alert(" Please enter a valid Number (e.g. XXX-XXX-XXXX)");
		obj.focus();
		return false;
	}
}