1.删除某select下除第一个以外的option：
1 $("#selectId option:not(:first)").remove()
2.JS实现双击事件（双击删除本身）
1 function removeThis(obj){ 2 var rangeId = obj.id; 3 debugger 4 $("#"+rangeId).each(function(index){ 5 $(this).dblclick(function(){ 6 $("#"+rangeId).remove(); 7 }); 8 9 }); 10 11 }
3.select的change()方法失效问题
先上个简单代码
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title>例子</title> 6 <script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"> 7 </script> 8 <script> 9 $("#selectId").change(function(){ 10 alert($('#selectId option:selected').val()); 11 }); 12 </script> 13 </head> 14 <body> 15 <select id="selectId" name="example"> 16 <option value="option1">option1</option> 17 <option value="option2">option2</option> 18 <option value="option3">option3</option> 19 <option value="option4">option4</option> 20 </select> 21 </body> 22 </html>
这是错误的代码，所以无效，应该调用ready()：
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title>例子</title> 6 <script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"> 7 </script> 8 <script> 9 $(document).ready(function(){ 10 11 $("#selectId").change(function(){ 12 alert($('#selectId option:selected').val()); 13 }); 14 15 }); 16 </script> 17 </head> 18 <body> 19 <select id="selectId" name="example"> 20 <option value="option1">option1</option> 21 <option value="option2">option2</option> 22 <option value="option3">option3</option> 23 <option value="option4">option4</option> 24 </select> 25 </body> 26 </html>
4.js实现div高度随背景图片的大小进行改变
主要是tongguojs来进行获取和设置，代码案例如下：
1 <!DOCTYPE html> 2 <html lang="en"> 3 <style> 4 body { 5 background: black; 6 } 7 8 .divClass { 9 width: 1000px; 10 height: 1000px; 11 margin: 0 auto; 12 background-image: url('https://kanjiantu.com/images/2019/06/16/-ID_5942171e4cc697c94698b.md.jpg'); 13 background-repeat: no-repeat; 14 15 } 16 </style> 17 <head> 18 <script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script> 19 <script> 20 $(document).ready(function () { 21 22 var image_url = $('#divId').css('background-image'), 23 image; 24 image_url = image_url.match(/^url("?(.+?)"?)$/); 25 26 if (image_url[1]) { 27 image_url = image_url[1]; 28 image = new Image(); 29 // just in case it is not already loaded 30 $(image).load(function () { 31 var bgHeight = image.height; 32 var bgWidth = image.width; 33 var divWidth = $('#divId').width(); 34 var divHeight = (divWidth*bgHeight)/bgWidth; 35 $('#divId').height(divHeight+"px"); 36 }); 37 image.src = image_url; 38 } 39 40 }); 41 </script> 42 </head> 43 <body> 44 <div id="divId" class="divClass"> 45 </div> 46 </body> 47 </html>
5.实现禁止右键和键盘打开控制台
1 <script type='text/javascript'> 2 //禁用右键 3 window.οncοntextmenu=function(){return false;} 4 //禁止任何键盘敲击事件 5 window.onkeydown = window.onkeyup = window.onkeypress = function () { 6 window.event.returnValue = false; 7 return false; 8 } 9 </script>