// Function to preload an image, using a helper function "deletemyself".
function image_preload (cursrc) {
 var curimg = document.createElement('img')
 document.body.appendChild(curimg)
 curimg.style.display = 'none'
 curimg.onload = deletemyself(curimg)
 curimg.src = cursrc
 function deletemyself(curimg) {document.body.removeChild(curimg); curimg = null; delete curimg}
 return true
}