' +'<td>'+ arr[i] + '</td>'+'</tr>')//)[0]);};arr.splice(0, 250);控制台日志(片段，arr，arr.length)；返回 dfd.notify([arr, fragment])};$.when(重绘())//`done` 回调.then(函数(数据){$("#results").html(data.join(","));删除片段；}//`fail` 回调， 空值//`progress` 回调，功能(数据){//log ，显示任务的进度"控制台日志(数据)；$("progress").val(data[1].length);$("output:first").text(Math.floor(data[1].length/100) + "%");$("output:last").text(data[1].length +" of "+ len + " items processing");$("#results").html("正在处理数据...");如果(数据[0].长度){var s = setTimeout(function() {重绘()}, 100)} 别的 {clearTimeout(s);dfd.resolve(数据[1]);}})})<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script><progress min="0" max="10000"></progress><output for="progress"></output><output for="progress"></output><br/><table id="results"></table>
jsfiddle http://jsfiddle.net/guest271314/ess28zLh/
I'm currently using AJAX with Django Framework.
I can pass asynchronous POST/GET to Django, and let it return a json object.
Then according to the result passed from Django, I will loop through the data, and update a table on the webpage.
The HTML for the table:
<!-- Modal for Variable Search-->
<div class="modal fade" id="variableSearch" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">×</span><span class="sr-only">Close</span></button>
<h4 class="modal-title" id="myModalLabel">Variable Name Search</h4>
</div>
<div class="modal-body">
<table id="variableSearchTable" class="display" cellspacing="0" width="100%">
<thead>
<tr>
<th> Variable Name </th>
</tr>
</thead>
</table>
<p>
<div class="progress">
<div class="progress-bar progress-bar-striped active" id="variableSearchProgressBar" role="progressbar" aria-valuenow="45" aria-valuemin="0" aria-valuemax="100" style="width: 45%">
<span class="sr-only">0% Complete</span>
</div>
</div>
</p>
<p>
<div class="row">
<div class="col-lg-10">
<button class="btn btn-default" type="button" id="addSearchVariable" >Add</button>
</div>
</div>
</p>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" id="variableSearchDataCloseButton" data-dismiss="modal">Close</button>
</div>
</div>
</div>
</div>
Basically it is a bootstrap 3 modal, with jQuery DataTable, and with a progress bar to show the user the current progress.
The Javascript that is used to get Django results:
$('#chartSearchVariable').click(function(event)
{
$('#chartConfigModal').modal("hide");
$('#variableSearch').modal("show");
var csrftoken = getCookie('csrftoken');
var blockname = document.getElementById('chartConfigModalBlockname').value;
$('#variableSearchProgressBar').css('width', "0%").attr('aria-valuenow', "0%");
event.preventDefault();
$.ajax(
{
type:"GET",
url:"ajax_retreiveVariableNames/",
timeout: 4000000,
data:
{
'csrfmiddlewaretoken':csrftoken,
'blockname':blockname
},
success: function(response)
{
if(response.status == "invalid")
{
$('#chartConfigModal').modal("hide");
$('#variableSearch').modal("hide");
$('#invalid').modal("show");
}
else
{
configurationVariableChart.row('').remove().draw(false);
for (i = 0 ; i < response.variables.length; i++)
{
configurationVariableChart.row.add(
$(
'<tr>' +
'<td>' + response.variables[i] + '</td>' +
'<tr>'
)[0]);
}
configurationVariableChart.draw();
$('#variableSearchProgressBar').css('width', "100%").attr('aria-valuenow', "100%");
}
},
failure: function(response)
{
$('#chartConfigModal').modal("hide");
$('#variableSearch').modal("hide");
$('#invalid').modal("show");
}
});
return false;
});
$('#addSearchVariable').click(function(event)
{
$('#variableSearch').modal("hide");
$('#chartConfigModal').modal("show");
document.getElementById('chartConfigModalVariable').value = currentVariableNameSelects;
});
$('#variableSearchDataCloseButton').click(function(event)
{
$('#variableSearch').modal("hide");
$('#chartConfigModal').modal("show");
});
The problem is with the updating table part:
configurationVariableChart.row('').remove().draw(false);
for (i = 0 ; i < response.variables.length; i++)
{
configurationVariableChart.row.add(
$(
'<tr>' +
'<td>' + response.variables[i] + '</td>' +
'<tr>'
)[0]);
}
configurationVariableChart.draw();
$('#variableSearchProgressBar').css('width', "100%").attr('aria-valuenow', "100%");
Since the response.variables can be over 10k, and it will freeze the web browser, even though it is still drawing.
I'm pretty new to Web Design (less than 4 months), but I assume it's because they are all running on the same thread.
Is there a way in Javascript to do threading/async? I had a search, and the results were deferred/promise which seems very abstract at the moment.
解决方案
Try processing retrieved data incrementally.
At piece below , elements generated in blocks of 250 , primarily utilizing jQuery deferred.notify() and deferred.progress().
When all 10,000 items processed , the deferred object is resolved with the collection of 10,000 elements. The elements are then added to document at single call to .html() within deferred.then()'s .done() callback ; .fail() callback cast as null .
Alternatively , could append elements to the document in blocks of 250 , within deferred.progress callback ; instead of at the single call within deferred.done , which occurs upon completion of the entire task.
setTimeout is utilized to prevent "freeze the web browser" condition .
$(function() {
// 10k items
var arr = $.map(new Array(10000), function(v, k) {
return v === undefined ? k : null
});
var len = arr.length;
var dfd = new $.Deferred();
// collection of items processed at `for` loop in blocks of 250
var fragment = [];
var redraw = function() {
for (i = 0 ; i < 250; i++)
{
// configurationVariableChart.row.add(
// $(
fragment.push('<tr>' +
'<td>' + arr[i] + '</td>' +
'</tr>')
// )[0]);
};
arr.splice(0, 250);
console.log(fragment, arr, arr.length);
return dfd.notify([arr, fragment])
};
$.when(redraw())
// `done` callbacks
.then(function(data) {
$("#results").html(data.join(","));
delete fragment;
}
// `fail` callbacks
, null
// `progress` callbacks
, function(data) {
// log , display `progress` of tasks
console.log(data);
$("progress").val(data[1].length);
$("output:first").text(Math.floor(data[1].length / 100) + "%");
$("output:last").text(data[1].length +" of "+ len + " items processed");
$("#results").html("processing data...");
if (data[0].length) {
var s = setTimeout(function() {
redraw()
}, 100)
} else {
clearTimeout(s);
dfd.resolve(data[1]);
}
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<progress min="0" max="10000"></progress><output for="progress"></output>
<output for="progress"></output><br />
<table id="results"></table>
jsfiddle http://jsfiddle.net/guest271314/ess28zLh/
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