function validaEmail(vMail) 
{
	if (isEmail2(vMail))
   		return(true)
 	else
 	{
   		alert("Por favor, informe um e-mail válido");
		document.form.f_Mail.value='';
		document.form.f_Mail.focus();
   		return(false);
 	}
}
function isEmail2(who) 
{
	var email=/^[A-Za-z0-9]+([_\.-][A-Za-z0-9]+)*@[A-Za-z0-9]+([_\.-][A-Za-z0-9]+)*\.([A-Za-z]){2,4}$/i;
	return(email.test(who));
}
//************************************************************************************************************************************************************************  
function openWindow(url,largura,altura,top,left)
{
	top=((top/2)-(altura/2));
	left=((left/2)-(largura/2));
	prop = 'toolbar=no, ';
	prop += 'location=no, ';
	prop += 'directories=no, ';
	prop += 'status=no, ';
	prop += 'menubar=no, ';
	prop += 'scrollbars=yes, ';
	prop += 'resizable=no, ';
	prop += 'menubar=no, ';
	prop += 'top ='+top+', ';
	prop += 'left='+left+', ';
	prop += 'width='+largura+', ';
	prop += 'height='+altura;
	window.open(url, altura, prop);
}
<!--..................................................................................................-->

function clickNS(e) 
{
	if (document.layers||(document.getElementById&&!document.all)) 
	{
		if (e.which==2||e.which==3) 
		{
			(mensagem);return false;
		}
	}
}
if (document.layers) 
{
	document.captureEvents(Event.MOUSEDOWN);
	document.onmousedown=clickNS;
}
else
{
	document.onmouseup=clickNS;document.oncontextmenu=clickIE;
}
document.oncontextmenu=new Function("return false")

var mensagem="";
function clickIE() 
{
	if (document.all) 
	{
		(mensagem);return false;
	}
}
    var asciiF2        = 113;
    var asciiF3        = 114;
    var asciiF4        = 115;
    var asciiF5        = 116;
    var asciiF6        = 117;
    var asciiF11       = 122;
    var asciiF12       = 123;
    var asciiF1        = 112;
    if(document.all){
        document.onkeydown = onKeyPress;
    }else if (document.layers || document.getElementById){
        document.onkeypress = onKeyPress;
    }
    function onKeyPress(evt) {
        window.status = '';
        var oEvent = (window.event) ? window.event : evt;
        var nKeyCode =  oEvent.keyCode ? oEvent.keyCode : oEvent.which ? oEvent.which : void 0;
        var bIsFunctionKey = false;
        if(oEvent.charCode == null || oEvent.charCode == 0){
            bIsFunctionKey = (nKeyCode >= asciiF1 && nKeyCode <= asciiF12)
        }
        var sChar = String.fromCharCode(nKeyCode).toUpperCase();
        var oTarget = (oEvent.target) ? oEvent.target : oEvent.srcElement;
        var sTag = oTarget.tagName.toLowerCase();
        var sTagType = oTarget.getAttribute("type");
        var bAltPressed = (oEvent.altKey) ? oEvent.altKey : oEvent.modifiers & 1 > 0;
        var bShiftPressed = (oEvent.shiftKey) ? oEvent.shiftKey : oEvent.modifiers & 4 > 0;
        var bCtrlPressed = (oEvent.ctrlKey) ? oEvent.ctrlKey : oEvent.modifiers & 2 > 0;
        var bRet = true; 
       if(sTagType != null){sTagType = sTagType.toLowerCase();}
        if(bIsFunctionKey){ // Capture and stop these keys
            bRet = false;
        }else if(bCtrlPressed && (sChar == 'R')){ // block Control + R
            bRet = false;
        }   
        if(!bRet){
            try{
                oEvent.returnValue = false;
                oEvent.cancelBubble = true;
                if(document.all){ //IE
                    oEvent.keyCode = 0;
                }else{ //NS
                    oEvent.preventDefault();
                    oEvent.stopPropagation();
                }
            //msg='Por favor, procure não utilizar';
			alert(msg);
            }
			catch(ex)
			{
                alert(msg);
            }
        }
        return bRet;
    }

/* ------------------------------------------------------------------------------------- */