This time I will show you how to verify the correct email address in JS. What are the precautions for verifying the correct email address in JS? The following is a practical case, let's take a look.
I recently worked on a front-end project, which requires that the input data must contain the @ symbol and the period (.). At the same time, @ cannot be the first character of the email address, and there must be at least one period after @.1: Code
nbsp;html> <meta> <title>利用JavaScript验证是否符合电子邮箱地址</title> <script> // 创建第一个函数validate_emil()并包含两个参数 function validate_email(field, alerttxt) { with (field) { //利用indexOf() 方法返回某个指定的字符串值在字符串中首次出现的位置--定义一个变量apos将第一次出现的“@”赋值给apos apos = value.indexOf("@"); //利用lastIndexOf() 方法返回一个指定的字符串值最后出现的位置,在一个字符串中的指定位置从后向前搜索-- //stringObject.lastIndexOf(searchvalue,fromindex) //fromindex 可选的整数参数。规定在字符串中开始检索的位置。它的合法取值是 0 到 stringObject.length - 1。如省略该参数,则将从字符串的最后一个字符处开始检索。 dotpos = value.lastIndexOf("."); // 判断符合"@"的位置,或者"."的位置是否在"@"的后面 if (apos < 1 || dotpos - apos < 2) { // 利用alert()弹出一个警告窗来执行alerttxt的操作 // 邮箱地址不符合 alert(alerttxt); return false; } else { // 邮箱地址符合 return true; } } } // 创建第二个函数validate_form()并包含一个参数 function validate_form(thisform) { with (thisform) { if (validate_email(email, "Not a valid e-mail address!") == false) { // 利用focus()将输入焦点移至对象上 email.focus(); return false; } } } </script> <!-- onsubmit是一个验证表单功能,为true提交, -->
2: Result
controller receives js and passes json parameters
js implements front-end and back-end Json transmission to each other
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