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iwato

Using AJAX to Fill a DIV with HTML Content that Depends on Javascript Functionality and CSS

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BACKGROUND:  My objective is to replace the content of an existent <div> element with new content that depends on newly loaded javascript, css, and a JSON object retrieved from a PHP processing file by an AJAX call.  To this end I have written the following brief piece of code.  To be clear the script contained in wordcount.js depends on the value of wordmax.  Further this same script is triggered when text is entered into a <textarea> form control found in newsletter.html.

 Please review the code and answer the questions that follow.

.click(function() {
	$('#main').html('');
	ajax_obj = $.ajax({
		url: 'newsletter_filler.php',
		data: {name : 'personal, length : 200},
		dataType: JSON,
		statusCode: {
			404: function() {
			alert( "Page not found" );
		}},
		success: function(jsonData) {
			$.getScript('wordcount.js', function(data) {
				var wordmax = jsonData;
			});
			$.get('newsletter.css', function(data) {
				$('head style').append(data);
			}
			$.get('newsletter.html', function(data) {
				$('#main').html(data);
			}
		} 
	});
}

QUESTION ONE:  Under the assumption that all of the code in the called files has been properly written and that the content of the .css and .html files is properly placed will the script contained in wordcount.js execute properly when triggered by the content of newsletter.html?

QUESTION TWO:  Will the content of the files newsletter.css and newsletter.html find their proper place and function as one might expect from such code, if it had been placed in the main document in the elements indicated by jQuery selector at the outset?

Roddy

 

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The CSS and HTML will work as intended.

I do not know how jQuery's getScript() method works, their documentation does not make it clear what is passed to the callback function, it just says "data" but that could refer to the file's contents, or something else. In any case, the following line of code will do nothing because it's local to the callback function:

var wordmax = jsonData;

You need to do something with the wordmax variable if you want it to work.

If wordcount.js has a function in it, you could pass wordmax to that function as a parameter, but considering that wordmax contains data that's already in wordcount.js, you probably shouldn't have to do that.

Another thing to note is that the order in which the HTML, CSS and JS are returned from your function calls is unpredictable because they are asynchronous. The JS might load first and try to manipulate HTML that does not yet exist.

  • Like 1

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OK.  I have rearranged wordcount.js so that it appears as a function, load it with $.getScript() in the AJAX success function, and call it with a callback function assigned to $.getScript().

WORDCOUNT.JS

function setWordConstraint(id, max) {
	$(id + ' span.word_limit').text(max);
	$(id + ' textarea').on('keydown', function(e) {
		var words = $.trim(this.value).length ? this.value.match(/\S+/g).length : 0;
		if (words <= max) {
			$(id + ' span.display_count').text(words);
			$(id + ' span.words_remaining').text(max-words);
		}else{
			if (e.which !== 8) e.preventDefault();
		}
	});
}

AJAX SCRIPT

$.ajax({
    url: 'newsletter_filler.php',
    data: {name : 'personal', length : 200},
    dataType: JSON,
    statusCode: {
        404: function() {
        alert( "Page not found" );
    }},
    success: function(jsonData) {
        console_log(jsonData);
        $.getScript('wordcount.js', function(jsonData) {
            $.each(jsonData, function(subfield, obj) {
                setWordConstraint(obj.id, obj.length);
            });
        });
    } 
});

OUTPUT PRODUCED BY newsletter_filler.php WHEN CALLED BY AJAX

{"personal":{"id":"#personal","length":"200"}}

THE HTML

<div id='personal' style='margin-top:1em;'>
    <label for='personal' style='color:green;'>Self-Introduction</label><br />
    <textarea name='personal' placeholder="Enter this week's abstract here!"></textarea><br />
    Word Count: <span class='display_count'>0</span>  Words Remaining: <span class='words_remaining'>0</span>
    <br />A <span class='word_limit'>max</span>-word abstract on this week's topic
</div><!-- end div#letter_abstract -->

Please note I cannot even get the above console_log() statement to reproduce the output that I am certain is generated by newsletter_filler.php.

There are no error messages in the Javascript Console.  None!

Roddy

Edited by iwato

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I think you might want to add a "#" to the id selector in these lines of code:

$("#" + id + ' span.word_limit').text(max);
$("#" + id + ' textarea').on('keydown', function(e) {
$("#" + id + ' span.display_count').text(words);
$("#" + id + ' span.words_remaining').text(max-words);

To write to the console, it's console.log()

 

  • Thanks 1

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Thanks for the correction, but even writing console.log(jsonData); fails to produce any visible output.

Also, the id variable contains the # already.  Look at the output from newsletter_filler.php.  I will write it again.

{"personal":{"id":"#personal","length":"200"}}

And, please note that the above result appears as the output in the resource panel.  The above string is created by the AJAX call.   In effect, the call succeeds, the success function fails.  Once again, I am baffled.

Is there something that could be preventing the produced output from being read by the AJAX call?

Roddy

Edited by iwato

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I am making progress.  The value of dataType was not enclosed in quotation marks.  There is still more to be done, though.

Roddy

 

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Try this

            $.ajax({
                url: 'newsletter_filler.php',
                data: {name: 'personal', length: 200},
                dataType: 'JSON',
                statusCode: {
                    404: function() {
                        alert("Page not found");
                    }},
                success: function(jsonData) {
                    console.log(jsonData);
                    $.getScript('wordcount.js').done(function() {
                        setWordConstraint(jsonData.personal['id'], jsonData.personal['length']);
                    });
                }
            });

The done() make sure script has completed, I don't know why used each function, as it will only loop through one set of json associated  index row data? unless you plan to expand on this where multiple row of data will be read.

Edited by dsonesuk
  • Like 1

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Got it!  This works.

$(document).ready(function() {
    $.ajax({
        url: 'newsletter_filler.php',
        data: {name : 'personal', length : 200},
        dataType: 'JSON',
        statusCode: {
            404: function() {
            alert( "Page not found" );
        }},
        success: function(jsonData) {
            $.getScript('wordcount.js', function(data) {
                $.each(jsonData, function(subfield, obj) {
                    setWordConstraint(obj.id, obj.length);
                });
            });
        } 
    });
});

Roddy

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