10 jQuery Code Snippets for Effective Web Development

In the past few years, jQuery has been the most widely used JavaScript script library. Today we will provide you with the 10 most practical jQuery code snippets for web developers. Developers in need can save them. Beginners can also use it to learn jQuery~

1. Detect Internet Explorer version
When it comes to CSS design, for developers and designers Internet Explorer has always been a problem. Even though the dark ages of IE6 are over and IE is becoming less and less popular, it's still a good thing to detect easily. Of course, the code below can also be used to detect other browsers.

$(document).ready(function() {
   if (navigator.userAgent.match(/msie/i) ){
    alert('I am an old fashioned Internet Explorer');
   }
});

#2. Sliding smoothly to the top of the page
This is the most widely used jQuery effect: clicking on a link will slide smoothly Move the page to the top. Nothing new here, but every developer must occasionally write similar functions

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

3. Fixed at the top
Very Useful code snippet which allows an element to be fixed on top. Super useful for navigation buttons, toolbars or important information boxes.

$(function(){
 var $win = $(window)
 var $nav = $('.mytoolbar');
 var navTop = $('.mytoolbar').length && $('.mytoolbar').offset().top;
 var isFixed=0;
 processScroll()
 $win.on('scroll', processScroll)
 function processScroll() {
 var i, scrollTop = $win.scrollTop()
 if (scrollTop >= navTop && !isFixed) { 
 isFixed = 1
 $nav.addClass('subnav-fixed')
 } else if (scrollTop <= navTop && isFixed) {
 isFixed = 0
  $nav.removeClass(&#39;subnav-fixed&#39;)
 }
}

4. Replace the html mark with other content
jQuery makes it easy to replace the html mark with another thing. The possibilities are endless.

$('li').replaceWith(function(){
 return $("<div />").append($(this).contents());
});

#5. Detecting window width
Now that mobile devices are more common than outdated computers, it is easier to detect a smaller window width. will be very helpful. Luckily, it's super easy to do with jQuery.

var responsive_viewport = $(window).width();
/* if is below 481px */
if (responsive_viewport < 481) {
  alert(&#39;Viewport is smaller than 481px.&#39;);
} /* end smallest screen */

#6. Automatically locate and repair damage Picture
If your site is large and already running online Over the years, you've more or less come across a corrupted image somewhere on the interface. This useful function can help detect a corrupted image and replace it with your preferred image, notifying visitors of the problem.

$('img').error(function(){
 $(this).attr('src', 'img/broken.png');
});

#7. Detect copy, paste and cut operations
Using jQuery you can easily detect copy and paste according to your requirements. Paste and cut operations.

$("#textA").bind('copy', function() {
  $('span').text('copy behaviour detected!')
}); 
$("#textA").bind('paste', function() {
  $('span').text('paste behaviour detected!')
}); 
$("#textA").bind('cut', function() {
  $('span').text('cut behaviour detected!')
});

#8. Automatically add the attribute of target="blank" when encountering an external link
When linking to an external link When opening a site, you may use the target="blank" attribute to open the site in a new interface. The problem is that the target="blank" attribute is not a valid W3C attribute. Let's use jQuery to remedy this: the following code will detect whether the link is an external link, and if so, it will automatically add a target="blank" attribute.

var root = location.protocol + '//' + location.host;
$('a').not(':contains(root)').click(function(){
  this.target = "_blank";
});

9. The transparency effect that gradually increases or decreases when staying on the picture
Another "classic" code, it needs to put Get it in your toolbox, because you'll want to implement it from time to time.

$(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
  });
});

10. Disable the space bar when entering text or passwords
The space bar is not required in many form fields, for example, email , username, password, etc. Here is a simple trick you can use to disable the space bar in selected input.

$('input.nospace').keydown(function(e) {
 if (e.keyCode == 32) {
 return false;
 }
});

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