function isblank(s)
{
    for(var i = 0; i < s.length; i++) {
        var c = s.charAt(i);
        if ((c != ' ') && (c != '\n') && (c != '\t')) return false;
    }
    return true;
}

// This is the function that performs form verification. It will be invoked
// from the onSubmit() event handler. The handler should return whatever
// value this function returns.
function verify(f)
{

    var msg;
    var empty_fields = "";
    var errors = "";

    // Loop through the elements of the form, looking for all 
    // text and textarea elements that don't have an "optional" property
    // defined. Then, check for fields that are empty and make a list of them.
    // Also, if any of these elements have a "min" or a "max" property defined,
    // then verify that they are numbers and that they are in the right range.
    // Put together error messages for fields that are wrong.
    
   for(var i = 0; i < f.length; i++) 
   	{
        	var e = f.elements[i];
        	
        	if (((e.type == "text") || (e.type == "textarea") ||  (e.type =="select-one")) && !e.optional) 
        	{
        	
 
            		// first check if the field is empty
            		if ((e.value == null) || (e.value == "") || isblank(e.value)) 
            		{
                		empty_fields += "\n          " + e.realname;                		
                		continue;
            		}

            	// Now check for fields that are supposed to be numeric.
            	if (e.numeric || (e.min != null) || (e.max != null)) 
            	{ 
                	var v = parseFloat(e.value);
                	if ( isNaN(v) || isNaN(e.value) || ((e.min != null) && (v < e.min)) || ((e.max != null) && (v > e.max))) 
                	{
                    		errors += "- The field " + e.realname + " must be a number";                    		
                	}
            	}
            	
            	if (e.email)
            	{
            	
            		if(e.value.indexOf("@") == -1)
            		{
            			errors += e.realname + " Must be a valid email address";            		
            		}
		}            	            	      
            	
            	
            	if (e.type =="select-one")
		   {			
			 if (e.selectedIndex == 0)
			  {				
			    empty_fields += "\n          " + e.realname;						
			    continue;
			  }
				
		   }
        	
        	}
        }


    // Now, if there were any errors, display the messages, and
    // return false to prevent the form from being submitted. 
    // Otherwise return true.
    if (!empty_fields && !errors) return true;

    msg  = "______________________________________________________\n\n"
    msg += "The form was not submitted because of the following error(s).\n";
    msg += "Please correct these error(s) and re-submit.\n";
    msg += "______________________________________________________\n\n"

    if (empty_fields) 
    {
        msg += "- The following required field(s) are empty:" + empty_fields + "\n\n\n";

        if (errors) msg += "\n";
    }
    msg += errors;

    alert(msg);
    return false;
}