自己的一套，
存在读者本地（localStorage），不占服务器、不跨设备。
后台「搜索记录」里的数据是另一套，一条都不受这里影响。 */
(function () {
var KEY = 'szw_searchhist';
var SHOW = 10; /* 面板里最多显示几条 */
var KEEP = 30; /* 本地最多存几条 */
function read() {
try { return JSON.parse(localStorage.getItem(KEY) || '[]') || []; }
catch (e) { return []; }
}
function write(list) {
try { localStorage.setItem(KEY, JSON.stringify(list)); } catch (e) {}
}
function esc(s) {
return String(s == null ? '' : s)
.replace(/&/g, '&').replace(//g, '>').replace(/"/g, '"');
}
/* 记一条：已存在的先删掉再放到最前面，所以最新的永远在最上 */
function add(word) {
word = String(word || '').replace(/^\s+|\s+$/g, '');
if (!word) return;
var list = read(), out = [word], i;
for (i = 0; i < list.length; i++) {
if (list[i] !== word) out.push(list[i]);
}
if (out.length > KEEP) out = out.slice(0, KEEP);
write(out);
}
function render() {
var box = document.getElementById('szwHistList');
if (!box) return 0;
var list = read(), h = '', n = 0, i;
for (i = 0; i < list.length && n < SHOW; i++) {
if (!list[i]) continue;
h += '' + esc(list[i]) + '';
n++;
}
box.innerHTML = h || '还没有搜索记录';
var as = box.querySelectorAll('a[data-w]');
for (i = 0; i < as.length; i++) {
as[i].onclick = function () {
var inp = document.getElementById('szwSearchInput');
var fm = document.getElementById('szwSearchForm');
if (inp) inp.value = this.getAttribute('data-w');
if (fm) fm.submit();
return false;
};
}
return n;
}
function init() {
var inp = document.getElementById('szwSearchInput');
var fm = document.getElementById('szwSearchForm');
var panel = document.getElementById('szwHistPanel');
var clr = document.getElementById('szwHistClear');
if (!inp || !panel) return;
/* 提交时把关键词记下来 */
if (fm) {
fm.onsubmit = function () { add(inp.value); return true; };
}
inp.onfocus = function () {
render();
panel.style.display = 'block';
};
inp.onclick = function (e) {
render();
panel.style.display = 'block';
if (e && e.stopPropagation) e.stopPropagation();
};
if (clr) {
clr.onclick = function (e) {
write([]); render();
if (e && e.stopPropagation) e.stopPropagation();
return false;
};
}
document.addEventListener('click', function (e) {
if (panel.style.display !== 'block') return;
var n = e.target;
while (n) { if (n === panel || n === inp) return; n = n.parentNode; }
panel.style.display = 'none';
});
/* 搜索结果页：把地址里的关键词也记上，直接点结果页链接过来的也能留痕 */
try {
var m = location.search.match(/[?&]q=([^&]+)/);
if (m) add(decodeURIComponent(m[1].replace(/\+/g, ' ')));
} catch (e) {}
}
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', init);
} else { init(); }
})();