结合AJAX的PHP开发之后退、前进和刷新(3)

＜script type="text/javascript" src="history.js"＞＜/script＞
＜script type="text/javascript"＞
var myHistory = new HistoryStack();
myHistory.load();
function do_add()
{
　var num = Math.round(Math.random() * 1000);
　myHistory.addResource(num);
　display();
　return false;
}
function do_back()
{
　myHistory.go(-1);
　display();
}
function do_forward()
{
　myHistory.go(1);
　display();
}
function do_reload()
{
　myHistory.go(0);
}
function display()
{
　// Display history buttons
　var str = '';
　if (myHistory.hASPrev()) {
str += '＜a href="#" onclick="do_back(); return false;"＞'
+ '＜img src="icons/back_on.gif" alt="Back"
/＞＜/a＞ ';
　} else {
str += '＜img src="icons/back_off.gif" alt="" /＞ ';
　}
　if (myHistory.hasNext()) {
str += '＜a href="#" onclick="do_forward(); return false;"＞'
+ '＜img src="icons/forward_on.gif" alt="Forward" /＞'
+ '＜/a＞ ';
　} else {
str += '＜img src="icons/forward_off.gif" alt="" /＞ ';
　}
　str += '＜a href="#" onclick="do_reload(); return false;"＞'
+ '＜img src="icons/reload.gif" alt="Reload"
/＞＜/a＞';
　document.getElementById("historybuttons").innerHTML = str;
　// Display the current history stack, highlighting the current
　// position.
　var str = '＜div＞History:＜/div＞';
　for (i=0; i ＜ myHistory.stack.length; i++) {
if (i == myHistory.current) {
　str += '＜div＞＜b＞' + myHistory.stack[i] +
'＜/b＞＜/div＞';
} else {
　str += '＜div＞' + myHistory.stack[i] + '＜/div＞';
}
　}
　document.getElementById("output").innerHTML = str;
}
window.onload = function () {
　display();
};
＜/script＞ 

＜div id="historybuttons"＞＜/div＞ 

＜script type="text/javascript" src="history.js"＞＜/script＞ 

var myHistory = new HistoryStack();
myHistory.load(); 

function get_table_link ( $title, $start, $step ) {
　$link = "myHistory.addResource('table-$start-$step'); "
　."x_get_table($start, $step, to_window); "
　."return false;";
　return '＜a href="#" onclick="' . $link . '"＞' . $title.'＜/a＞';
}
function get_image_link ( $title, $index ) {
　$link = "myHistory.addResource('image-$index'); "
　."x_get_image($index, to_window); "
　."return false;";
　return '＜a href="#" onclick="' . $link . '"＞' . $title .'＜/a＞';
} 

display_history_buttons(); 

function display_history_buttons()
{
　var str = '';
　if (myHistory.hASPrev()) {
str += '＜a href="#" onclick="do_back(); return false;"＞
＜img src="icons/back_on.gif" alt="Back" /＞＜/a＞';
　} else {
str += '＜img src="icons/back_off.gif" alt="" /＞';
　}
　if (myHistory.hasNext()) {
str += '＜a href="#" onclick="do_forward(); return false;"＞
＜img src="icons/forward_on.gif" alt="Forward" /＞＜/a＞';
　} else {
str += '＜img src="icons/forward_off.gif" alt="" /＞';
　}
　str += '＜a href="#" onclick="do_reload(); return false;"＞
＜img src="icons/reload.gif" alt="Reload" /＞＜/a＞';
　document.getElementById("historybuttons").innerHTML = str;
}