Creating dynamic html with json taking too much time - javascript

I am working on preparing some dynamic html with jquery and json object. but the problem is that when my json object has around 1500 rows it takes ages to load.
is there a way to load the thing faster.
Some code.
$(jQuery.each(jsonObject.AvailableColumns, function (i, l) {
if (type == "manual") {
innerList1 += '<li newText="" valueFormat="' + l.ValueFormat + '" scaleID="' + l.ScaleID + '" scaleType="' + l.ScaleType + '" hasWeights="' + l.HasWeights + '" customColumnType="' + l.CustomColumnType + '" class="" id="li_' + controlId + '"><span id="span_' + controlId + '" title = "' + l.QuestionText + '">' + getDisplayString(l.QuestionText) + '</span><a class="actionLeft"></a></li>';
}
else if (type = "exportall") {
innerList2 += CreateLiWithSpans('li_' + controlId, l.QuestionText, true, false, l.ScaleID, l.ScaleType, l.HasWeights, l.CustomColumnType, l.ValueFormat);
}
controlId++;
}));
$("#itemList").html(innerlist1);
EDIT : createliwithspan method
function CreateLiWithSpans(id, html, isLeft, isAddAll, scaleID, scaleType, hasWeights, customColumnType, valueFormat, newText) {
var ancClass = isLeft ? 'actionRight' : 'actionLeft';
var liObject = "";
if (newText == null) {
newText = "";
}
if (isLeft) {
liObject = '<li newtext="' + newText + '" valueFormat="' + valueFormat + '" scaleID="' + scaleID + '" scaleType="' + scaleType + '" hasWeights="' + hasWeights + '" customColumnType="' + customColumnType + '" class="" id="' + id + '"><span id="span_' + id + '" title = "' + html + '">' + getDisplayString(html) + '</span><span style="margin:0 10px 0 20px;pagging:0"><input title = "' + (newText == "" ? html : newText) + '" type="text" id="' + id + 'displayText" value="' + (newText == "" ? html : newText) + '" /><span style="color:Red; width:100%;" id="' + id + 'displayTextError"></span></span><span style="float:left">' + CreateDropDown('ddl_' + id, valueFormat, hasWeights) + '</span><a class="' + ancClass + '"></a></li>';
}
else {
liObject = '<li newtext="' + newText + '" valueFormat="' + valueFormat + '" scaleID="' + scaleID + '" scaleType="' + scaleType + '" hasWeights="' + hasWeights + '" customColumnType="' + customColumnType + '" class="" id="' + id + '"><span id="span_' + id + '" title = "' + html + '">' + getDisplayString(html) + '</span><a class="' + ancClass + '"></a></li>';
}
return liObject;
}

You can use for loop instead of jQuery.each, that will be faster. Store the itemCount before the loop, and use that:
itemCount = jsonData.items.length;
for(var i = 0; i < itemCount; i++ ) {
...
You can also use use an array instead of string concatenation, like so:
var innerList = [];
... // inside the loop
innerList.push(CreateLiWithSpans('li_' + controlId, l.QuestionText, true, false, l.ScaleID, l.ScaleType, l.HasWeights, l.CustomColumnType, l.ValueFormat));
... // after the loop
$("#itemList").html(innerList.join(''));
This will be faster in IE, I'm not sure about other js engines.
These two methods will not make a significant difference, so you should try implementing a client side pagination from json. (Not by hiding and showing divs, by rendering only visible page into the DOM).

Instead of waiting for the loop to end to append your data, why not actively append the data as you process it. This will allow the user to get immediate feedback instead of waiting for the whole thing to process. Other than this, I'd stick with my original comment to page the data.
$(jQuery.each(jsonObject.AvailableColumns, function (i, l) {
if (type == "manual") {
$("#itemList").append( '<li newText="" valueFormat="' + l.ValueFormat + '" scaleID="' + l.ScaleID + '" scaleType="' + l.ScaleType + '" hasWeights="' + l.HasWeights + '" customColumnType="' + l.CustomColumnType + '" class="" id="li_' + controlId + '"><span id="span_' + controlId + '" title = "' + l.QuestionText + '">' + getDisplayString(l.QuestionText) + '</span><a class="actionLeft"></a></li>');
}
else if (type = "exportall") {
$("#itemList2").append(CreateLiWithSpans('li_' + controlId, l.QuestionText, true, false, l.ScaleID, l.ScaleType, l.HasWeights, l.CustomColumnType, l.ValueFormat));
}
controlId++;
}));

Try replacing jQuery.each with a plain old for...in loop. Using jQuery.each adds overhead that you don't need.
Don't concatenate strings inside your loop. Instead, .push them onto an array variable and use .join('') to build the string all at once at the end.
You may need to eliminate CreateLiWithSpans as a separate function in order to fully implement (2).

Changing from using jQuery.each to a standard javascript for loop should speed it up a bit. Make sure that you save the length to a variable like this though:
for(var i = 0, len = jsonObject.AvailableColumns.length; i < len; i++){
var l = jsonObject.AvailableColumns[i];
// Continue with rest of code
}
Probably won't be a huge increase but every little helps.
Also try lowering the number of function calls you make as these have added overhead (not usually an issue, but in a large loop it can help). Unless the code is shared between functions try doing it inline and see how much that speeds it up.

Related

jQuery When After Each Loop

I have six static html questions and then 3-4 questions being generated by JSON dynamically based upon a form choice made on a page before. What I'm trying to do is generate the questions, then create a progress bar based on the final number of questions created. Where I'm having trouble is using the jQuery when done method after my each loop. It is firing after the first iteration instead of the last. I have tried populating an array "Qs" and passing the array, after reading some other posts, but what I have hasn't worked. I would really like to segment my code and clean it up as much as possible, so I'm trying to stay away from nesting it.
var Qs = [];
var generateQs = function (){
var $dept = sessionStorage.getItem("sFGeneralDepartment1");
var $qWrapper = $("#assessmentTool");
$.getJSON("js/dept-questions.json", function(data) {
var key = $dept;
var vals = [];
switch(key) {
case 'Information technology':
vals = data.IT;
break;
case 'Finance':
vals = data.FIN;
break;
case 'Human resources':
vals = data.HR;
break;
case 'Marketing':
vals = data.MKT;
break;
default:
vals = data.OT;
break;
}
$.each(vals, function(index, value) {
var $cleanID = (value.qID).replace(/q/g, '');
$qWrapper.append('<div class="question-container rangeIcon disabled" id="' + value.qID + '"><p>Question ' + $cleanID +'</p> <h4>' + value.questionText + '</h4><ul class="answer-container"></ul></div>');
$.each(value.answers, function(i, answer) {
var $aID = answer.aID;
var $radioBtn = '<div class="radioBtn"><span class="radioBtnInner"></span></div>';
$('.question-container#' + value.qID + ' .answer-container').append('<li class="survey-item"><div class="icon-holder" id="' + $aID + '"><img src="img/' + answer.iconFileName + '" width="' + answer.iconWidth +'" height="'+ answer.iconHeight + '"/></div><input type="radio" id="'+ $aID + '" value="' + answer.pointValue + '"><label for="' + $aID + '" class="radio" data-popover="'+ answer.popoverText + '">' + $radioBtn + '<span class="labelTopText">' + answer.labelTopText + '<span class="divider">/</span></span><span class="labelBottomText">' + answer.labelBottomText + '</span></label></li>');
});
Qs.push($cleanID);
});
console.log('done');
console.log(Qs);
});
};
$.when(generateQs($,Qs)).done(function() {
//create progress bar
console.log('starting');
var qCount = ($('.question-container').length + 1);
var qList = $('#progressBar');
for (var i = 0; i < qCount; i++){
qList.append('<li class="progress-bar-steps" data-item="q' + (i+1) + '">' + '<span class="step-text">' + (i+1) + '</span>' + '</li>');
$('.question-container').each(function (i, value){
var qId = $(this).attr('id');
if ($(this).hasClass("active")) {
$(this).css('opacity','1.0');
$('#progressBar').find("[data-item='" + qId + "']").addClass('active').html('<span class="step-text">' + (i+1) + '</span>');
$('.progress-bar-steps.active').next('.progress-bar-steps').addClass('next disabled-next').html('<span class="step-text">' + (i+2) + '</span>');
} else {
$(this).addClass('disabled');
}
});
}
});

jquery $.each not giving all the information in the table

Fiddle
I want to put the names of all record in my array into a table my array isn't index correctly so i used $.each instead of iterating over the using for loop. My problem is I only get to show the last element but if i try to show a value that is existing to both the array it is showing correctly.
What am i missing in this code.
Any idea is appreciated
This is my javascript
for (var i = 0; i < name.length; i++) {
var names = name[i].Names;
$.each(names, function (item, names) {
tr = $('<tr class=""/>');
//console.log(complainant[obj]);
//var names = complainant[obj];
//if(names.hasOwnProperty('fname')){
console.log(names.suffix);
var acronymc;
var upper = names.mname.toUpperCase();
if (upper) {
var matches = upper.match(/\b(\w)/g);
//var matches = upper.replace(/^(\S+)\s+(\S).*/, '$1 $2.');
//acronym = upper.slice(0,1);
var acronym1 = matches.join('');
acronymc = acronym1.slice(-1);
} else {
acronymc = '';
}
tr.append("<td id=''>" + "<span id='fname'>" + names.fname + "</span>" + " " + "<span id='mname'>" + acronymc + "</span>" + " " + "<span id='lname'>" + names.lname + "</span>" + " " + "<span id='suffix'>" + names.suffix + "</span>" + "</td>");
tr.append("<td id=''>" + '<span id="street">' + names.street + '</span>' + " " + '<span id="brgy">' + names.brgy + '</span>' + " " + '<span id="town">' + names.town + '</span>' + " " + '<span id="city">' + names.city + '</span>' + "</td>");
tr.append("<td id=''>" + names.contactnum + "</td>");
tr.append("<td id=''>" + "<a href='#' class='editcomplainant'>Edit</a>" + "/" + "<a href='#' class='delete'>Delete</a>" + "</td>");
//}
});
$("#nameslist").append(tr);
}
Put the $('#nameslist').append(tr); call inside the $.each block.
Here is a way of improving the creation of tds:
var html =
"<td>" +
"<span id='fname'/> " +
"<span id='mname'/> " +
"<span id='lname'/> " +
"<span id='suffix'/>" +
"</td>";
var td = $(html);
td.find('#fname').text(names.fname);
td.find('#mname').text(acronymc);
td.find('#lname').text(names.lname);
td.find('#suffix').text(names.suffix);
tr.apppend(td);
Why is this better (imho)?
You will not create unintentional html tags by having < and > inside the variables.
Appropriate escaping (auml codes) will be automatically generated
It is easier to read

Retrieve Flickr photo title AND description using jQuery

Annoyingly, the FlickrAPI provides the title and description of a photo in two separate methods. I'm having trouble getting the description of an image from Flickr and was wondering if you could highlight the error in my script.
for (var i = 0; i < photos.photo.length; i++) {
var descPhoto = "https://api.flickr.com/services/rest/?method=flickr.photos.getInfo&api_key="+API_KEY+"&photo_id="+photos.photo[i].id+"&format=json&nojsoncallback=1";
var descArr = [];
$.getJSON(descPhoto, function(data) {
var value = data.photo.description._content;
descArr.push(value);
});
link = 'https://farm' + photos.photo[i].farm + '.static.flickr.com/' + photos.photo[i].server + '/' + photos.photo[i].id + '_' + photos.photo[i].secret + '_';
title = this._htmlEscape( photos.photo[i].title );
var lightbox = "lightbox";
listItems +=
'<li ' + 'class="' + liClassNoDots + '">' +
'<a href="' + link + self.options.imageSize + '.jpg" title="' + title + '" class="' + aClassNoDots + '" target="_blank" data-lightbox="' + lightbox + '">' +
<img alt="' + title + '" src="' + link + self.options.thumbnailSize +'.jpg"/>' +
'<div class="hover-box">' +
'<p>' + descArr[i] + '</p>' +
'<button class="box-button view">View larger</button>' +
'<button class="box-button request">Request</button>' +
'</div>';
'</a>' +
'</li>';
}
Getting the title is fine and I've checked by API string calls and they work in the address bar of my browser.
I've used console.log() and the array is printed out correctly and I'm getting the descriptions. However, in each <p> tag the script is returning undefined in each instance.
However, if I run the script through the debugger the parapgraph tags are populated with the descriptions. Can somebody help?!
i think the problem is in following code::
..
$.getJSON(description, function(desc) {
value = desc.photo[ i ].description._content;
});
the service url returns photo object whereas you are using photo array, change to:
..
$.getJSON(description, function(desc) {
value = desc.photo.description._content;
console.log( value );
});

Javascript SHIFT and POP on Associative Array

Using a regular array I am able to grab the image src from an array using shift() and pop(); I would like to do the same thing using an associative array to add a name and id.
Single Array
var products = ['product1.jpg'];
$('#products').append('<img src="' + products.shift() + '">');
Associative Array
var products = [{id:'1',name:'product 1',image:'product1.jpg'}];
$('#products').append('<img id="' + products.shift() + '" name="' + products.shift() + '" src="' + products.shift() + '">');
You're using a regular array full of objects, so shift and pop will work, but return you the object.
var products = [{id:'1',name:'product 1',image:'product1.jpg'}];
var prod = products.shift();
$('#products').append('<img id="' + prod.id + '" name="' + prod.name + '" src="' + prod.image + '">');
This line: var products = [{id:'1',name:'product 1',image:'product1.jpg'}]; declares an array with a single value inside. The single value is an object with the properties id, name, and image. When you call shift on the array, the value returned will be this object.
var products = [{id:'1',name:'product 1',image:'product1.jpg'}];
for(var i =0; i < products.length; i++){
var product = products[i];
$('#products').append('<img id="' + product.id + '" name="' + product.name + '" src="' + product.image + '">');
}
shift() is going to pull the whole object out of the index, not piece by piece like in your example.
You would need to access the object by name to get what you want.
var products = [{id:'1',name:'product 1',image:'product1.jpg'}, {id:'2',name:'product 2',image:'product2.jpg'}];
var currentProduct = products.shift();
$('#products').append('<img id="' + currentProduct.id + '" name="' + currentProduct.name + '" src="' + currentProduct.image + '">');
to loop through it
while(products.length>0){
var currentProduct = products.shift();
$('#products').append('<img id="' + currentProduct.id + '" name="' + currentProduct.name + '" src="' + currentProduct.image + '">');
}
better performance loop would be one write to the DOM
var strOut = "";
while(products.length>0){
var currentProduct = products.shift();
strOut += '<img id="' + currentProduct.id + '" name="' + currentProduct.name + '" src="' + currentProduct.image + '">';
}
$('#products').append( strOut );
You can cache the shift, and use the object's properties:
var products = [{id:'1',name:'product 1',image:'product1.jpg'}];
var product = products.shift();
$('#products').append('<img id="' + product.id
+ '" name="' + product.name
+ '" src="' + product.image + '">');
You can store the values differently, as a multi-dimensional array:
var products = [['1','product 1','product1.jpg']];
var product = products.shift();
$('#products').append('<img id="' + product.shift()
+ '" name="' + product.shift()
+ '" src="' + product.shift() + '">');

Filter JQuery list with URL

I need to modify some code already in place. There's a block of code that filters a JQuery list using the URL to populate the search input.
E.g.
http://***/store/mobile/page/productList.page?search=football
Automatically enters "football" in the search bar.
Now I'd need to filter the list, without using the search bar.
So lets say my URL would look something like this :
http://***/store/mobile/page/productList.page?football
This would filter the list with football without using the search bar.
Here's the code I need to change. Please tell me if my question is unclear.
$('div[data-url*="productList"]').live("pageshow", function() {
filterValue = getParameterByName("search", location.search);
if (filterValue) {
$('input[data-type="search"]').val(filterValue);
}
refreshList();
});
and:
$.each(catalog.products,
function(index, value) {
if ((!filterValue )
|| value.name.toUpperCase().indexOf(filterValue.toUpperCase()) != -1
|| value.brand.toUpperCase().indexOf(filterValue.toUpperCase()) != -1)
{
items.push('<li id="' + index + '">' +
'<a data-identity="productId" href="./details.page?productId=' + index + '" >' +
'<img class="ui-li-thumb" src="' + value.thumbnail + '"/>' +
'<p>' + value.brand + '</p>' +
'<h3>' + value.name + '</h3>' +
'<span class="ui-li-count">' + value.price + ' $</span></li>') +
'</a>';
}
});
if there will always be only 1 parameter after ? than you could simply get it from page location in javascript, e.g.
var url = document.location;
var params = url.split("?");
filterValue = params[params.length-1]
if (filterValue) {
$('input[data-type="search"]').val(filterValue);
}
refreshList();
example: http://jsfiddle.net/yPgPc/

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