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About Anthony Levensalor
Experience
I have been programming in Java and Javascript since 1998. I run a web development company that specializes in Ajax front ends with PHP/MySQL back ends. I am a Sun Certified Java 2 Developer, and have done nothing but web applications for the last two years in my business

Past/Present clients
Monster.com, Compuware Corporation, Flextronics International, Pragmatech Software, Open Travel Software, The Loss Mitigation Institute, Raw Story Media, Page One News Media.

You are here: Experts > Computing/Technology > Focus on JavaScript > Javascript > thumbnail alignment in javascript

Topic: Javascript

Expert: Anthony Levensalor
Date: 11/30/2007
Subject: thumbnail alignment in javascript

Question
Hi Anthony,

Can you please tell me how I can adjust this script so that the enlarged image will display ABOVE the cursor and not below as it is currently?
Here is the URL to the page I am working on:
http://www.randomlychallenge.com/TabTest2.php

Here is my source:
var offsetfrommouse=[0, 20]; //image x,y offsets from cursor position in pixels. Enter 0,0 for no offset
var displayduration=0; //duration in seconds image should remain visible. 0 for always.

var defaultimageheight = 100;   // maximum image size.
var defaultimagewidth = 100;   // maximum image size.

var timer;

function gettrailobj(){
if (document.getElementById)
return document.getElementById("preview_div").style
}

function gettrailobjnostyle(){
if (document.getElementById)
return document.getElementById("preview_div")
}

function truebody(){
return (!window.opera && document.compatMode && document.compatMode!="BackCompat")? document.documentElement : document.body
}

function hidetrail(){
  gettrailobj().display= "none";
  document.onmousemove=""
  gettrailobj().left="-500px"
  clearTimeout(timer);
}

function showtrail(imagename,title,width,height){
  i = imagename
  t = title
  w = width
  h = height
  timer = setTimeout("show('"+i+"',t,w,h);",200);
}
function show(imagename,title,width,height){

   var docwidth=document.all? truebody().scrollLeft+truebody().clientWidth : pageXOffset+window.innerWidth - offsetfrommouse[0]
  var docheight=document.all? Math.min(truebody().scrollHeight, truebody().clientHeight) : Math.min(window.innerHeight)

  if( (navigator.userAgent.indexOf("Konqueror")==-1 || navigator.userAgent.indexOf("Firefox")!=-1 || (navigator.userAgent.indexOf("Opera")==-1 && navigator.appVersion.indexOf("MSIE")!=-1)) && (docwidth>650 && docheight>500)) {
     ( width == 0 ) ? width = defaultimagewidth: '';
     ( height == 0 ) ? height = defaultimageheight: '';

     width+=30
     height+=55
     defaultimageheight = height
     defaultimagewidth = width

     document.onmousemove=followmouse;


     newHTML = '<div class="border_preview" style="width:'+ width +'px;height:'+ height +'px"><div id="loader_container"><div id="loader"><div align="center">Loading template preview...</div><div id="loader_bg"><div id="progress"> </div></div></div></div>';
     newHTML = newHTML + '<h2 class="title_h2">' + ' '+title + '</h2>'

      newHTML = newHTML + '<div class="preview_temp_load"><img onload="javascript:remove_loading();" src="' + imagename + '" border="0"></div>';
     newHTML = newHTML + '</div>';

     if(navigator.userAgent.indexOf("MSIE")!=-1 && navigator.userAgent.indexOf("Opera")==-1 ){
        newHTML = newHTML+'<iframe src="about:blank" scrolling="no" frameborder="0" width="'+width+'" height="'+height+'"></iframe>';
     }

     gettrailobjnostyle().innerHTML = newHTML;
     gettrailobj().display="block";
  }
}

function followmouse(e){

  var xcoord=offsetfrommouse[0]
  var ycoord=offsetfrommouse[1]

  var docwidth=document.all? truebody().scrollLeft+truebody().clientWidth : pageXOffset+window.innerWidth-15
  var docheight=document.all? Math.min(truebody().scrollHeight, truebody().clientHeight) : Math.min(window.innerHeight)

  if (typeof e != "undefined"){
     if (docwidth - e.pageX < defaultimagewidth + 2*offsetfrommouse[0]){
        xcoord = e.pageX - xcoord - defaultimagewidth; // Move to the left side of the cursor
     } else {
        xcoord += e.pageX;
     }
     if (docheight - e.pageY < defaultimageheight + 2*offsetfrommouse[1]){
        ycoord += e.pageY - Math.max(0,(2*offsetfrommouse[1] + defaultimageheight + e.pageY - docheight - truebody().scrollTop));
     } else {
        ycoord += e.pageY;
     }

  } else if (typeof window.event != "undefined"){
     if (docwidth - event.clientX < defaultimagewidth + 2*offsetfrommouse[0]){
        xcoord = event.clientX + truebody().scrollLeft - xcoord - defaultimagewidth; // Move to the left side of the cursor
     } else {
        xcoord += truebody().scrollLeft+event.clientX
     }
     if (docheight - event.clientY < (defaultimageheight + 2*offsetfrommouse[1])){
        ycoord += event.clientY + truebody().scrollTop - Math.max(0,(2*offsetfrommouse[1] + defaultimageheight + event.clientY - docheight));
     } else {
        ycoord += truebody().scrollTop + event.clientY;
     }
  }
  gettrailobj().left=xcoord+"px"
  gettrailobj().top=ycoord+"px"

}// JavaScript Document

Thank you for any assistance to can offer me.

Mark

Answer
It's actually really simple. I had the same trouble, and I spent a lot of time waaaay overcomplicating it.

Here's how you get the real mouse position in both IE7 and FireFox:

elm.onmouseover = function (e)
{
e = e || window.event
var x, y;

if (window.event)
     {
       x = window.event.clientX
       y= window.event.clientY

       x+= document.body.scrollLeft;
  y+= document.body.scrollTop;
     } else {
       x= e.pageX;
       y = e.pageY;
     } // if

     // now, adjust your element however you like
     elmToDisplay.style.top = y - 100 // 100 pixels up
     elmToDisplay.styl.left = x + 100 // 100 pixels right

   }; // function

And that's it.

Hope this helps,
~A!

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