我有一段有点大的 javascript/ajax 代码，我想看看是否可以使其更有效地运行而不删除任何函数。
我的问题是我收到一个名为“getlastupdate.php”的页面，它只有 14 个数字，这些数字是数据库表上次更新的日期和时间。
格式为:
- 年-月-日-HH-mm:ss
这是一个示例:20130724082105
我取出了“:.-”，因为我们不需要它。
我的 javascript 代码将此与另一个 ajax GET 进行比较，该 ajax GET 重复从“getlastupdate.php”获取当前日期/时间。如果发现两个值不相同，则会触发另一个 GET 来获取行信息。
它获取更新的行信息并将其显示在浏览器中。最后它获取整个更新的表并将其放回到表中(表排序器)。
一切似乎都工作正常，但是当脚本添加新表信息并删除旧表信息时，我注意到一些滞后？或者至少我认为这是 LAG 的主要原因。
这是代码:
<link type="text/css" rel="stylesheet" href="tablesorter/qtip/jquery.qtip.min.css" />
<script type="text/javascript" src="tablesorter/jquery-1.10.2.min.js"></script>
<!-- blue theme stylesheet -->
<link rel="stylesheet" href="tablesorter/final/theme.blue.css">
<!-- tablesorter plugin -->
<script src="tablesorter/final/jquery.tablesorter.js"></script>
<!-- tablesorter widget file - loaded after the plugin -->
<script src="tablesorter/final/jquery.tablesorter.widgets.js"></script>
<!-- START: toastmessage Notify -->
<link type="text/css" href="tablesorter/final/toastmessage/jquery.toastmessage-min.css" rel="stylesheet"/>
<script type="text/javascript" src="tablesorter/final/toastmessage/jquery.toastmessage-min.js"></script>
<!-- END: toastmessage Notify -->
<script type="text/javascript" src="tablesorter/qtip/jquery.qtip.min.js"></script>
<script type="text/javascript">
var comper;
function checkComper() {
var SvInfo;
var onResponse = function(comperNow) { // comperNow is the latest date/time var
//check if comper has been set / first time method is called
if (comper === undefined) {
comper = comperNow;
return;
}
if (comper !== comperNow) {
var Vinfoo;
$.get("getlastupdate2.php", function(primaryAddType){
// alert("Data: " + primaryAddType);
Vinfoo = primaryAddType;
// show a message to the visitor ---->
//alert(Vinfoo);
$().toastmessage('showNoticeToast', Vinfoo);
});
$('#append').trigger('click'); // UPDATE THE TABLE BUT IT TAKES 3-4 SEC. AND I NEED IT TO SPEED UP!
// and update comper to show the date/time from comperNow
comper = comperNow;
}
};
$.get('getlastupdate.php', onResponse);
}
var tid = setInterval(checkComper, 2000); // repeat myself
$(function() {
$('[title!=""]').qtip({}); // A bit better. Grab elements with a title attribute that isn't blank. <-- CUSTOM TOOLTIP
var $table = $("table.tablesorter");
$("#append").click(function(e) {
e.preventDefault();
$.get('updatetable.php', function(data)
{
$table
.find('tbody')
.html('')
.append(data);
$table.trigger("update", [true]);
$('[title!=""]').qtip({}); // A bit better. Grab elements with a title attribute that isn't blank. <-- CUSTOM TOOLTIP
});
});
// call the tablesorter plugin
$("table.tablesorter").tablesorter({
theme: 'blue',
// hidden filter input/selects will resize the columns, so try to minimize the change
widthFixed : true,
//sortList: [[2,0],[1,0]],
// initialize zebra striping and filter widgets
widgets: ["saveSort", "zebra", "filter"],
// headers: { },
widgetOptions : {
// If there are child rows in the table (rows with class name from "cssChildRow" option)
// and this option is true and a match is found anywhere in the child row, then it will make that row
// visible; default is false
filter_childRows : false,
// if true, a filter will be added to the top of each table column;
// disabled by using -> headers: { 1: { filter: false } } OR add class="filter-false"
// if you set this to false, make sure you perform a search using the second method below
filter_columnFilters : true,
// css class applied to the table row containing the filters & the inputs within that row
filter_cssFilter : 'tablesorter-filter',
// class added to filtered rows (rows that are not showing); needed by pager plugin
filter_filteredRow : 'filtered',
// add custom filter elements to the filter row
// see the filter formatter demos for more specifics
filter_formatter : null,
// add custom filter functions using this option
// see the filter widget custom demo for more specifics on how to use this option
filter_functions : null,
// if true, filters are collapsed initially, but can be revealed by hovering over the grey bar immediately
// below the header row. Additionally, tabbing through the document will open the filter row when an input gets focus
filter_hideFilters : false, // true, (see note in the options section above)
// Set this option to false to make the searches case sensitive
filter_ignoreCase : true,
// if true, search column content while the user types (with a delay)
filter_liveSearch : true,
// jQuery selector string of an element used to reset the filters
filter_reset : 'button.reset',
// Delay in milliseconds before the filter widget starts searching; This option prevents searching for
// every character while typing and should make searching large tables faster.
filter_searchDelay : 300,
// if true, server-side filtering should be performed because client-side filtering will be disabled, but
// the ui and events will still be used.
filter_serversideFiltering: false,
// Set this option to true to use the filter to find text from the start of the column
// So typing in "a" will find "albert" but not "frank", both have a's; default is false
filter_startsWith : false,
// Filter using parsed content for ALL columns
// be careful on using this on date columns as the date is parsed and stored as time in seconds
filter_useParsedData : false
}
});
// External search
// buttons set up like this:
// <button type="button" class="search" data-filter-column="4" data-filter-text="2?%">Saved Search</button>
$('button.search').click(function(){
/*** first method *** data-filter-column="1" data-filter-text="!son"
add search value to Discount column (zero based index) input */
var filters = [],
col = $(this).data('filter-column'), // zero-based index
txt = $(this).data('filter-text'); // text to add to filter
filters[col] = txt;
// using "table.hasFilters" here to make sure we aren't targetting a sticky header
$.tablesorter.setFilters( $('table.hasFilters'), filters, true ); // new v2.9
/** old method (prior to tablsorter v2.9 ***
var filters = $('table.tablesorter').find('input.tablesorter-filter');
filters.val(''); // clear all filters
filters.eq(col).val(txt).trigger('search', false);
******/
/*** second method ***
this method bypasses the filter inputs, so the "filter_columnFilters"
option can be set to false (no column filters showing)
******/
/*
var columns = [];
columns[5] = '2?%'; // or define the array this way [ '', '', '', '', '', '2?%' ]
$('table').trigger('search', [ columns ]);
*/
return false;
});
});
</script>
如果我注释掉这一行，我就找到了 LAG 的来源:
$('#append').trigger('click'); // UPDATE THE TABLE BUT IT TAKES 3-4 SEC. AND I NEED IT TO SPEED UP! it will speed everything up but how do I get it to speed up or even slow down so that it doesn't lock up the current page.
如果我注释掉以下内容，也会加快加载速度:
var $table = $("table.tablesorter");
$("#append").click(function(e) {
e.preventDefault();
$.get('updatetable.php', function(data)
{
$table
.find('tbody')
.html('')
.append(data);
$table.trigger("update", [true]);
// ******** +++++++++++ **************
$('[title!=""]').qtip({}); // <-- CUSTOM TOOLTIP THIS SLOWS DOWN THE LOADING ALSO!!!!!
// ******** +++++++++++ **************
});
});
@Abudoul Sy， 这是我现在拥有的:
<script type="text/javascript">
// I should be put at the top of the file (not in an Ajax Loop)
var compileHTML = function (html) {
var div = document.createElement("div");
div.innerHTML = html;
var fragment = document.createDocumentFragment();
while ( div.firstChild ) {
fragment.appendChild( div.firstChild );
}
return fragment
};
var comper;
function checkComper() {
var SvInfo;
var onResponse = function(comperNow) { // comperNow is the latest date/time var
//check if comper has been set / first time method is called
if (comper === undefined) {
comper = comperNow;
return;
}
if (comper !== comperNow) {
var Vinfoo;
$.get("getlastupdate2.php", function(primaryAddType){
// alert("Data: " + primaryAddType);
Vinfoo = primaryAddType;
// show a message to the visitor ---->
//alert(Vinfoo);
$().toastmessage('showNoticeToast', Vinfoo);
});
$('#append').trigger('click'); // UPDATE THE TABLE BUT IT TAKES 3-4 SEC. AND I NEED IT TO SPEED UP!
// and update comper to show the date/time from comperNow
comper = comperNow;
}
};
$.get('getlastupdate.php', onResponse);
}
var tid = setInterval(checkComper, 2000); // repeat myself
$(function() {
$(document).ready(function()
{
$('[title!=""]').qtip({}); // A bit better. Grab elements with a title attribute that isn't blank. <-- CUSTOM TOOLTIP
})
var $table = $("table.tablesorter");
//Keeping a reference variable to
var $tableContents = $table.find('tbody');
$("#append").click(function(e) {
e.preventDefault();
$.get('updatetable.php', function(data)
{
$table
//When ajax is done
var compiledHtml = window.compileHTML(data);
$tableContents.html(compiledHTML);
$table.trigger("update", [true]);
$(document).ready(function()
{
$('[title!=""]').qtip({}); // A bit better. Grab elements with a title attribute that isn't blank. <-- CUSTOM TOOLTIP
})
});
});
// call the tablesorter plugin
$("table.tablesorter").tablesorter({
theme: 'blue',
// hidden filter input/selects will resize the columns, so try to minimize the change
widthFixed : true,
//sortList: [[2,0],[1,0]],
// initialize zebra striping and filter widgets
widgets: ["saveSort", "zebra", "filter"],
headers: { 8: { sorter: false, filter: false } },
widgetOptions : {
// If there are child rows in the table (rows with class name from "cssChildRow" option)
// and this option is true and a match is found anywhere in the child row, then it will make that row
// visible; default is false
filter_childRows : false,
// if true, a filter will be added to the top of each table column;
// disabled by using -> headers: { 1: { filter: false } } OR add class="filter-false"
// if you set this to false, make sure you perform a search using the second method below
filter_columnFilters : true,
// css class applied to the table row containing the filters & the inputs within that row
filter_cssFilter : 'tablesorter-filter',
// class added to filtered rows (rows that are not showing); needed by pager plugin
filter_filteredRow : 'filtered',
// add custom filter elements to the filter row
// see the filter formatter demos for more specifics
filter_formatter : null,
// add custom filter functions using this option
// see the filter widget custom demo for more specifics on how to use this option
filter_functions : null,
// if true, filters are collapsed initially, but can be revealed by hovering over the grey bar immediately
// below the header row. Additionally, tabbing through the document will open the filter row when an input gets focus
filter_hideFilters : false, // true, (see note in the options section above)
// Set this option to false to make the searches case sensitive
filter_ignoreCase : true,
// if true, search column content while the user types (with a delay)
filter_liveSearch : true,
// jQuery selector string of an element used to reset the filters
filter_reset : 'button.reset',
// Delay in milliseconds before the filter widget starts searching; This option prevents searching for
// every character while typing and should make searching large tables faster.
filter_searchDelay : 300,
// if true, server-side filtering should be performed because client-side filtering will be disabled, but
// the ui and events will still be used.
filter_serversideFiltering: false,
// Set this option to true to use the filter to find text from the start of the column
// So typing in "a" will find "albert" but not "frank", both have a's; default is false
filter_startsWith : false,
// Filter using parsed content for ALL columns
// be careful on using this on date columns as the date is parsed and stored as time in seconds
filter_useParsedData : false
}
});
// External search
// buttons set up like this:
// <button type="button" class="search" data-filter-column="4" data-filter-text="2?%">Saved Search</button>
$('button.search').click(function(){
/*** first method *** data-filter-column="1" data-filter-text="!son"
add search value to Discount column (zero based index) input */
var filters = [],
col = $(this).data('filter-column'), // zero-based index
txt = $(this).data('filter-text'); // text to add to filter
filters[col] = txt;
// using "table.hasFilters" here to make sure we aren't targetting a sticky header
$.tablesorter.setFilters( $('table.hasFilters'), filters, true ); // new v2.9
/** old method (prior to tablsorter v2.9 ***
var filters = $('table.tablesorter').find('input.tablesorter-filter');
filters.val(''); // clear all filters
filters.eq(col).val(txt).trigger('search', false);
******/
/*** second method ***
this method bypasses the filter inputs, so the "filter_columnFilters"
option can be set to false (no column filters showing)
******/
/*
var columns = [];
columns[5] = '2?%'; // or define the array this way [ '', '', '', '', '', '2?%' ]
$('table').trigger('search', [ columns ]);
*/
return false;
});
});
</script>
最佳答案
检查您的代码:
每次执行 Ajax 请求时，您都会执行以下操作:
$table
.find('tbody')
.html('')
.append(data);
$table.trigger("update", [true]);
解释一下它的作用:
- 你在 html 标签上调用
$.find(慢) - 您删除了表格的内容(导致浏览器将像素重新绘制为白色)
- 您要求浏览器的 DOM 解析整个 html 表，导致多次布局重新处理和重新绘制(非常糟糕)
- 调用表上的触发器(ok)
我认为，只要更好地处理数据就可以将处理速度加快无数倍，具体取决于表的大小。 考虑一下:
// I should be put at the top of the file (not in an Ajax Loop)
window.compileHTML = function (html) {
var div = document.createElement("div");
div.innerHTML = html;
var fragment = document.createDocumentFragment();
while ( div.firstChild ) {
fragment.appendChild( div.firstChild );
}
return fragment
};
//Keeping a reference variable to
var $tableContents = $table.find('tbody')
//When ajax is done
var compiledHtml = window.compileHTML(data);
$tableContents.html(compiledHtml);
$table.trigger("update", [true]);
编辑:如果compileHTML不起作用。
做几乎相同的事情(但不编译)的一个好方法是:
//put just after $table declaration
var $tableContents = $table.find('tbody')
//When ajax is done
var $html = $('<tbody/>').html(data);
$tableContents.replaceWith($html)
$table.trigger("update", [true]);
编辑:
我所做的是创建一个文档片段(在 DOM 之外)，让通过 compileHTML 进行的 html 处理不会在当前页面上发生任何事件。当一切完成后。
仅将创建的新 dom 树的根附加到 DOM，仅导致一次重绘:“与单元格和行一样多”将使您的浏览器看起来更稳定。
可选(不完全可选):
您的代码可能存在更多陷阱，但调查性能很困难。
我建议对 Chrome/Firebug 进行时间线检查-> 打开控制台(F12 或 Alt+shift+i)按“时间轴”选项卡。
按 (ctrl/cmd)+E 并更新 pass ，再按 ctrl+E，您将看到一些直方图，较大的条形意味着您的应用程序滞后/卡顿，然后您可以单击条形图查看所有调用的函数的堆栈跟踪，从而进行优化。
希望有帮助:)
关于javascript - 一切正常，但脚本中有 LAG？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17836543/