Handy and Useful jQuery Snippets for Developers

jQuery is a cross browser JavaScript library that helps developers and designers built and design powerful and responsive web programs and applications. It have actually made the coders writeless and do more with it. jQuery is helpful in designing page layout, adding application features and it also provides capabilities for developers to create plug-ins on top of the JavaScript library.

Handy and Useful jQuery Snippets for Developers

1. Preloading Images

(function($) {
  var cache = [];
  // Arguments are image paths relative to the current page.
  $.preLoadImages = function() {
    var args_len = arguments.length;
    for (var i = args_len; i--;) {
      var cacheImage = document.createElement('img');
      cacheImage.src = arguments[i];
      cache.push(cacheImage);
    }
  }

jQuery.preLoadImages("image1.gif", "/path/to/image2.png");

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2. Hover on/off

$("a").hover(
  function () {
    // code on hover over
  },
  function () {
    // code on away from hover
  }
);

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3. Smooth Scrolling to an anchor

$(document).ready(function() {
	$("a.topLink").click(function() {
		$("html, body").animate({
			scrollTop: $($(this).attr("href")).offset().top + "px"
		}, {
			duration: 500,
			easing: "swing"
		});
		return false;
	});
});

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4. Fade in/out on hover

$(document).ready(function(){
    $(".thumbs img").fadeTo("slow", 0.6); // This sets the opacity of the thumbs to fade down to 60% when the page loads

    $(".thumbs img").hover(function(){
        $(this).fadeTo("slow", 1.0); // This should set the opacity to 100% on hover
    },function(){
        $(this).fadeTo("slow", 0.6); // This should set the opacity back to 60% on mouseout
    });
});

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5.  Preventing anchor tags from loading

$("a").on("click", function(e){
  e.preventDefault();
});

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6. Scroll to Top

$("a[href='#top']").click(function() {
  $("html, body").animate({ scrollTop: 0 }, "slow");
  return false;
});

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7. Facebook like Image Gallery

var nextimage = "/images/some-image.jpg";
$(document).ready(function(){
window.setTimeout(function(){
var img = $("

").attr("src", nextimage).load(function(){
//all done
});
}, 100);
});

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8. Auto Populating Select Boxes Using jQuery and Ajax

$(function(){
$("select#ctlJob").change(function(){
$.getJSON("/select.php",{id: $(this).val(), ajax: 'true'}, function(j){
var options = '';
for (var i = 0; i < j.length; i++) {
options += '
' + j[i].optionDisplay + '

';
}
$("select#ctlPerson").html(options);
})
})
})

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9. Auto Replace Broken Images

// Safe Snippet
$("img").error(function () {
	$(this).unbind("error").attr("src", "missing_image.gif");
});

// Persistent Snipper
$("img").error(function () {
	$(this).attr("src", "missing_image.gif");
});

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10. Clear Form Data

function clearForm(form) {
  // iterate over all of the inputs for the form
  // element that was passed in
  $(':input', form).each(function() {
    var type = this.type;
    var tag = this.tagName.toLowerCase(); // normalize case
    // it's ok to reset the value attr of text inputs,
    // password inputs, and textareas
    if (type == 'text' || type == 'password' || tag == 'textarea')
      this.value = "";
    // checkboxes and radios need to have their checked state cleared
    // but should *not* have their 'value' changed
    else if (type == 'checkbox' || type == 'radio')
      this.checked = false;
    // select elements need to have their 'selectedIndex' property set to -1
    // (this works for both single and multiple select elements)
    else if (tag == 'select')
      this.selectedIndex = -1;
  });
};

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