function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.0
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && document.getElementById) x=document.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

<!-- Begin
// Set up the image files to be used.
var theImages = new Array() // do not change this
// To add more image files, continue with the
// pattern below, adding to the array.

theImages[0] = 'images/truck1.jpg'
theImages[1] = 'images/truck2.jpg'
theImages[2] = 'images/truck3.jpg'
theImages[3] = 'images/truck4.jpg'
theImages[4] = 'images/truck5.jpg'
theImages[5] = 'images/truck6.jpg'

// do not edit anything below this line

var j = 0
var p = theImages.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = theImages[i]
}
var whichImage = Math.round(Math.random()*(p-1));
function showImage(){
document.write('<img src="'+theImages[whichImage]+'" width=\"275\" height=\"347\" alt=\"Berry&#8217;s Tyre Service\">');
}
//  End -->

function ValidateForm(f){
      with(f){
         if (isEmpty(_1_Name.value)) {
            alert("Please enter your Name");
            _1_Name.focus();
            return false;
         }

         if (isEmpty(_2_Email_From.value)) {
            alert("Please enter your Email Address");
            _2_Email_From.focus();
            return false;
         }

         if ( !isEmail(_2_Email_From.value) ) {
            alert("Please enter a valid Email Address.");
            _2_Email_From.focus();
            return false;
         }

         if (!isEmpty(_3_Phone.value)) {
	         if (!IsNumber(_3_Phone.value, true)) {
            	alert("Please enter only numbers for your Phone");
            	_3_Phone.focus();
            	return false;
         	}
         }
   	}
   return true;
 }