Sometimes when we register an account and log in to the system, we can only submit when all verifications are passed. This requires Jquery to implement form verification. Today I will share with you a piece of code to implement form verification based on Jquery.
<html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <title>Reg</title> <style> .state1{ color:#aaa; } .state2{ color:#000; } .state3{ color:red; } .state4{ color:green; } </style> <script src="jquery.js"></script> <script> $(function(){ var ok1=false; var ok2=false; var ok3=false; var ok4=false; // 验证用户名 $('input[name="username"]').focus(function(){ $(this).next().text('用户名应该为3-20位之间').removeClass('state1').addClass('state2'); }).blur(function(){ if($(this).val().length >= 3 && $(this).val().length <=12 && $(this).val()!=''){ $(this).next().text('输入成功').removeClass('state1').addClass('state4'); ok1=true; }else{ $(this).next().text('用户名应该为3-20位之间').removeClass('state1').addClass('state3'); } }); //验证密码 $('input[name="password"]').focus(function(){ $(this).next().text('密码应该为6-20位之间').removeClass('state1').addClass('state2'); }).blur(function(){ if($(this).val().length >= 6 && $(this).val().length <=20 && $(this).val()!=''){ $(this).next().text('输入成功').removeClass('state1').addClass('state4'); ok2=true; }else{ $(this).next().text('密码应该为6-20位之间').removeClass('state1').addClass('state3'); } }); //验证确认密码 $('input[name="repass"]').focus(function(){ $(this).next().text('输入的确认密码要和上面的密码一致,规则也要相同').removeClass('state1').addClass('state2'); }).blur(function(){ if($(this).val().length >= 6 && $(this).val().length <=20 && $(this).val()!='' && $(this).val() == $('input[name="password"]').val()){ $(this).next().text('输入成功').removeClass('state1').addClass('state4'); ok3=true; }else{ $(this).next().text('输入的确认密码要和上面的密码一致,规则也要相同').removeClass('state1').addClass('state3'); } }); //验证邮箱 $('input[name="email"]').focus(function(){ $(this).next().text('请输入正确的EMAIL格式').removeClass('state1').addClass('state2'); }).blur(function(){ if($(this).val().search(/\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*/)==-1){ $(this).next().text('请输入正确的EMAIL格式').removeClass('state1').addClass('state3'); }else{ $(this).next().text('输入成功').removeClass('state1').addClass('state4'); ok4=true; } }); //提交按钮,所有验证通过方可提交 $('.submit').click(function(){ if(ok1 && ok2 && ok3 && ok4){ $('form').submit(); }else{ return false; } }); }); </script> </head> <body> <form action='do.php' method='post' > 用 户 名:<input type="text" name="username"> <span class='state1'>请输入用户名</span><br/><br/> 密 码:<input type="password" name="password"> <span class='state1'>请输入密码</span><br/><br/> 确认密码:<input type="password" name="repass"> <span class='state1'>请输入确认密码</span><br/><br/> 邮 箱:<input type="text" name="email"> <span class='state1'>请输入邮箱</span><br/><br/> <a href="javascript:;"><img class='submit' type='image' src='./images/reg.gif' / alt="Implement form validation based on Jquery_jquery" ></a> </form> </body> </html>
The above is the entire content of this article, I hope you all like it.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.


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