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/* |
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Fast filtering function using pre-sorted list elements |
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Dobrica Pavlinusic, dpavlin@rot13.org 2004-09-06 |
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Matko Andjelinic, matko.andjelinic@gmail.com 2004-09-09 (contributed OO implementation) |
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*/ |
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|
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|
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function BFilter(arr) { |
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this.id_cache = Array(); |
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// total number of hits |
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this.hits = 0; |
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|
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// this function is called for each result |
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this.result = function (arr) { |
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return '<li><a href="'+arr[1]+'">'+ |
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(this.hits % 2 == 0 ? '<span style="background: #e0e0e0;">' : '') + |
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arr[0] + |
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(this.hits % 2 == 0 ? '</span>' : '') + |
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'</a></li>'; |
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} |
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|
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// this function is called when updating innerHTML with results |
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this.display = function (html) { |
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return '<ul>'+html+'</ul>'; |
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} |
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|
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|
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if (! arr) { |
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this.debug("ERROR: can't search empty array"); |
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return; |
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} |
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|
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this.arr = arr; |
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this.debug("index has "+this.arr.length+" parts"); |
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|
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if (! arr.min_len) { |
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this.results("ERROR: index structure problem"); |
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return; |
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} else { |
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this.min_len = arr.min_len; |
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} |
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|
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this.debug("index part has "+this.min_len+" parts"); |
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|
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this.show_status(); |
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|
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} |
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|
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BFilter.prototype.element_id = function (id,no_alert) { |
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if (this.id_cache[id]) { |
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return this.id_cache[id]; |
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} else { |
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var el = document.getElementById(id); |
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if (el) { |
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this.id_cache[id] = el; |
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return el; |
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} else { |
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if (! no_alert) { |
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alert("can't find element id: "+id); |
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} else { |
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// don't look it up again |
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this.id_cache[id] = null; |
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} |
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} |
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} |
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return null; |
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} |
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|
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|
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BFilter.prototype.show_status = function (status) { |
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var html; |
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if (this.hits > 0) { |
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html = "shown "+this.hits+" entries"; |
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} else { |
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html = "no results"; |
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} |
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if (! status) { |
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html = "Enter "+this.min_len+" letter"+(this.min_len == 1 ? '' : 's')+" to filter entries"; |
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status = ""; |
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} |
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|
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var el = this.element_id("status"); |
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el.innerHTML = html+status+"\n"; |
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} |
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|
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BFilter.prototype.results = function (html,clean) { |
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|
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if (! html) { html = ""; } |
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|
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// results_div.style.cursor = 'wait'; // 'auto' |
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var results_div = this.element_id("results"); |
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if (clean) { |
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results_div.innerHTML = html; |
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} else { |
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results_div.innerHTML += this.display(html); |
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} |
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} |
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|
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|
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BFilter.prototype.debug = function (html) { |
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|
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//return; |
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|
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// check if debugging is on |
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if (! html) { return 1; } |
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|
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var debug_div = this.element_id("debug",1); |
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if (! debug_div) { return null; } |
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|
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debug_div.innerHTML += html + "<br>\n"; |
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|
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return null; |
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} |
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|
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|
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// modified binary search to find first element with substring |
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BFilter.prototype.binarySearch = function (arr, find) { |
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if (!arr || typeof (find) == "undefined" || !arr.length) { |
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return null; |
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} |
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var low = 0; |
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var high = arr.length - 1; |
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var middlearr = parseInt(arr.length / 2); |
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var lastTry; |
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while (low <= high) { |
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var mid = (low + high) / 2; |
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var aTry = (mid < 1) ? 0 : parseInt(mid); |
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|
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var curr = arr[aTry][0].substr(0,find.length).toLowerCase(); |
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this.debug("low="+low+" high="+high+" lastTry="+lastTry+" "+aTry+": "+curr); |
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if (curr < find) { |
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low = aTry + 1; |
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continue; |
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} |
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if (curr > find) { |
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high = aTry - 1; |
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continue; |
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} |
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if (curr == find) { |
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high = aTry - 1; |
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lastTry = aTry; |
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continue; |
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} |
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return aTry; |
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} |
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this.debug("lastTry="+lastTry); |
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|
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if (typeof (lastTry) != "undefined") { |
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return lastTry; |
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} else { |
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return null; |
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} |
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} |
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|
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BFilter.prototype.filter = function (document, find) { |
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|
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this.results('',1); |
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this.hits = 0; |
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|
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if (find.length < this.min_len) { |
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this.show_status(); |
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return; |
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} |
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|
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this.debug("filter: '"+find+"'"); |
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|
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var find_lc = find.toLowerCase(); |
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|
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var part = find_lc.substr(0,this.min_len); |
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|
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// no part found |
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if (! this.arr[part]) { |
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this.show_status(" for <em>"+find+"</em><br>"); |
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this.debug("no part "+part); |
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return; |
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} |
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|
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// start anim icon |
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//results("<img src=\"pie.gif\"> Please wait, filtering...\n",1); |
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|
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var i; |
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|
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// full part? (optimization) |
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if (find.length == this.min_len) { |
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var html = ''; |
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for (i = 0; i < this.arr[part].length; i++) { |
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html += this.result(this.arr[part][i]); |
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this.hits++; |
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} |
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this.results(html); |
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} else { |
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|
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var from = this.binarySearch(this.arr[part], find_lc); |
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|
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if (from != null) { |
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|
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this.debug("loop "+from+" ... "+this.arr[part].length); |
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|
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html = ''; |
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|
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for(i = from ; i < this.arr[part].length ; i++) { |
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if (this.arr[part][i][0].substring(0,find.length).toLowerCase() != find_lc) { |
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this.debug("loop exit at "+i); |
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break; |
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} |
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html += this.result(this.arr[part][i]); |
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this.hits++; |
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} |
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|
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this.results(html); |
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} |
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|
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} |
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|
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this.show_status(" for <em>"+find+"</em>"); |
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|
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} |
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