var clickmessage="本站图片不能保存"

function disableclick(e) {
if (document.all) {
if (event.button==2||event.button==3) {
if (event.srcElement.tagName=="IMG"){
alert(clickmessage);
return false;
}
}
}
if (document.layers) {
if (e.which == 3) {
alert(clickmessage);
return false;
}
}
}

function associateimages(){
for(I=0;I<document.images.length;I++)
document.images[I].onmousedown=disableclick;
}

if (document.all)
document.onmousedown=disableclick
else if (document.layers)
associateimages()