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JavaScript jQuery Basics (2014) Creating a Simple Lightbox Perform: Part 1

Posted by seema yadav
seema yadav
Courses Plus Student 345 Points

I am having a problem in understanding where to place '$' in front of the code.

var $overlay = $('<div id="overlay">saa</div>'); var $caption = $("<p></p>"); var $image = $("<img >");

$overlay.append($image); $overlay.append($caption); $( "body" ).append( $overlay );

$( "#imageGallery li a" ).click(function() { event.preventDefault(); var imageLocation = $(this).attr( "href" ); console.log(imageLocation); var imageCaption = $(this).children("img").attr("alt"); console.log(imageCaption); $image.attr("src", imageLocation); $caption.text(imageCaption);

$overlay.show(); });

$("#overlay").click(function(){ $overlay.hide(); });

For example when image and caption were appended to the body then no dollar sign is added before the code except for the one used for defining the variable, $overlay.append($image);

But when we appended overlay to body then $ was placed before the code. $( "body" ).append( $overlay );

Why in the first example dollar is added before it like- $$overlay.append($image);

2 Answers

Fernando Boza
Fernando Boza
25,384 Points
Fernando Boza
Fernando Boza
25,384 Points

Hi Seema remember that JQuery uses $ to know what element in the html or js file you want to modify.

Functions like append, next or attr, etc wouldn't need to add the $ because they are functions that change / modify the html and js elements, and we use the $ to specify which elements.

Jacob Mishkin
Jacob Mishkin
23,118 Points
Jacob Mishkin
Jacob Mishkin
23,118 Points

The $ sign used in front of your code is to denote jQuery. What is happening is that by using the $ sign jQuery is searching the DOM to find the element that you are requesting, then if found creates a new jQuery object for that element.

exmp:

$("#overlay").click(function(){ //the $("#overlay") is being searched in the DOM

$overlay.hide(); // if found creates the Jquery object here
});

if you would like to learn more check out this great reference jQuery