/////////////////////on page load//////////////
function loadDoc(j,x) 
{
	// for initial focus
	document.forms[j].elements[x].focus();
	return;
} //end of function
/////////////////////////////////////
<!-- to validae email address ------------!>
function validateEmail(j,x)
{
	if(document.forms[j].elements[x].value!="")
	{
	   pass=document.forms[j].elements[x].value.indexOf('@',0);
	   pass1=document.forms[j].elements[x].value.indexOf('.',0);
	   
	   if((pass==-1)||(pass1==-1))
	   {
			alert("Please enter a complete email address in the form: yourname@yourdomain.com");
			document.forms[j].elements[x].focus();
			return false;
	   }
	   else 
	   {
			var emailAdd=document.forms[j].elements[x].value;
			var i=1;
			var sLength=emailAdd.length;
		
			while((i<sLength)&&(emailAdd.charAt(i)!="@"))
			{
				i++;
			}
			if((i>=sLength)||(emailAdd.charAt(i)!="@"))
			{
				alert("Please enter a complete email address in the form: yourname@yourdomain.com"); 
				document.forms[j].elements[x].focus();
				return false;
			}
			else 
				i+=2;
			while((i<sLength)&&(emailAdd.charAt(i)!="."))
			{
				i++;
			}
			if((i>=sLength-1)||(emailAdd.charAt(i)!="."))
			{
				alert("Please enter a complete email address in the form: yourname@yourdomain.com"); 
				document.forms[j].elements[x].focus();
				return false;
			}
			if (isEmail(emailAdd) == false) 
			{
				alert("Please enter a valid email address.");
				document.forms[j].elements[x].focus();
				return false;
			} //end of if
		
		}  //end of else
	} //end of if
	return true;
}
//////////////////////////////////////////
<!--------------- check empty fields!>
function  fieldNotEmpty(j)
{
	for(i=0;i<document.forms[j].length-1;i++)
	{
		if (document.forms[j].elements[i].value=="")
		{
			alert("Empty field.\n Please enter a value here.");
			document.forms[j].elements[i].focus();
			return false;

		} //end of if
	} //end of for
	return true;
	
} //end of function
/////////////////////////////////////////////////
function validateNumber(j,x)
{
	// check for all numbers
    for (var i=0; i < document.forms[j].elements[x].value.length; i++)
    {
    	var ch = document.forms[j].elements[x].value.substring(i,i+1);
        if (ch < "0" || ch > "9" ) 
        {
            alert("Invalid characters entered.\nPlease enter only numbers (0-9).");
            document.forms[j].elements[x].focus();
            return false;
		} //end of if
    } //end of for
	return true;
} //end of function
//////////////////////////////////////////////
function validateTextOnlyAlphabets(j,x)
{
	//check for alphabets
	if(document.forms[j].elements[x].value!="")
	{
		var myname=document.forms[j].elements[x].value;
		if(isProper(myname)==false)
		 {
        	alert("Invalid characters entered.\nPlease enter only alphabets (a-z or A-Z).");
        	document.forms[j].elements[x].focus();
        	return false;
   	 	} //end of if
	} //end of if
	return true;
} //end of function
////////////////////////////////////////////////////////
function isProper(string)
{
	if (!string) 
	{
		return false;
	} //end of if
	var iChars = "*|,\":<>[]{}?`\';()@&$#%1234567890+=-*";
	for (var i = 0; i < string.length; i++)
	{
		if (iChars.indexOf(string.charAt(i)) != -1)
		{
			return false;
		} //end of if
    } //end of for
    return true;
} //end of function
////////////////////////////////////////////////////
///////////////////////////////////////////////////
<!-- Begin
function checkDecimals(j, x) 
{
	decallowed = 2;  // how many decimals are allowed?
	var fieldValue=document.forms[j].elements[x].value;
	var fieldName=document.forms[j].elements[x];
	//alert (fieldValue);
	if (fieldValue == "") 
	{
		alert("Empty field.\n  Please try again.");
		fieldName.select();
		fieldName.focus();
		return false;
	}
	else if (isNaN(fieldValue))
	{
		alert("Not a valid number.\n  Please try again.");
		fieldName.select();
		fieldName.focus();
		return false;
	}
	else if (fieldValue<1)
	{
		alert("Cannot be negative number.\n  Please try again.");
		fieldName.select();
		fieldName.focus();
		return false;
	}
	else 
	{
		if (fieldValue.indexOf('.') == -1) 
			fieldValue += ".";
		dectext = fieldValue.substring(fieldValue.indexOf('.')+1, fieldValue.length);
		
		if (dectext.length > decallowed)
		{
			alert ("Please enter a number with up to " + decallowed + " decimal places.\n  Please try again.");
			fieldName.select();
			fieldName.focus();
			return false;
		}
		
	}
	return true;
}
//  End -->
///////////////////////////////////////////////////