通过本文主要向大家介绍了javascript的同源策略,javascript表单验证,javascript表单事件,javascript表单校验,javascript表单等相关知识,希望对您有所帮助,也希望大家支持linkedu.com www.linkedu.com
简单的表单验证
html结构
<!-- validata.html --> <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Validata</title> </head> <body> <form id="form"> <label for="username">账号：</label><input id="username" type="text"><br> <label for="password">密码：</label><input id="password" type="password"><br> <label for="phonenum">手机：</label><input id="phonenum" type="text"><br> <input id="submit" type="button" value="提交"> </form> <p id="warn"></p> <script src="validata.js"></script> </body> </html></div>
首先先简单地实现以下这个功能
之后再用设计模式丰满
// validata.js
var form = document.getElementById('form'),
warn = document.getElementById('warn');
var validata = function(){
if(form.username.value === ''){
return warn.textContent = '账号不能为空';
}
if(form.password.value === ''){
return warn.textContent = '密码不能为空';
}
if(form.phonenum.value === ''){
return warn.textContent = '手机号不能为空';
}
var msg = {
username: form.username.value,
password: form.password.value,
phonenum: form.phonenum.value
}
//ajax('...', msg); ajax提交数据略
return warn.textContent = '用户信息已成功提交至服务器';
}
form.submit.onclick = function(){
validata();
}
</div>
然后分析以下代码
validata这个函数毫无复用性可言，除此之外存在两个问题
- 函数同时承担了验证和提交两个职责，违背单一职责原则
- 验证功能扩展性差，要想添加验证规则就必须深入函数内部，违反开放-封闭原则
所以我们需要对此进行改进
装饰模式重构
先来用装饰模式解决一下函数多职责问题
方法也很简单
改进一下AOP前置装饰函数（Function.prototype.before）
当扩展函数（beforeFn）返回false则不执行当前函数
然后令表单验证函数成为表单提交函数的前置装饰
这样提交前就会进行验证，若验证失败，就不会提交数据
var form = document.getElementById('form'),
warn = document.getElementById('warn');
Function.prototype.before = function(beforeFn){
var self = this;
return function(){
if(beforeFn.apply(this, arguments) === false)
return;
return self.apply(this, arguments);
}
}//改进的AOP前置装饰函数
var validata = function(){
if(form.username.value === ''){
warn.textContent = '账号不能为空';
return false;
}
if(form.password.value === ''){
warn.textContent = '密码不能为空';
return false;
}
if(form.phonenum.value === ''){
warn.textContent = '手机号不能为空';
return false;
}
}
var submitMsg = function(){ //将提交的功能从validata函数中提取出来
var msg = {
username: form.username.value,
password: form.password.value,
phonenum: form.phonenum.value
}
//ajax('...', msg);
return warn.textContent = '用户信息已成功提交至服务器';
}
submitMsg = submitMsg.before(validata);
//让表单验证函数成为表单提交函数的装饰者
form.submit.onclick = function(){
submitMsg();
};
</div>
策略模式重构
下面就该解决函数缺乏弹性的问题
使用策略模式就需要有策略对象/类和环境对象/类
毫无疑问策略对象中就应该装着校验规则
又考虑到页面可能不止有一个验证表单
最好写成工厂-类的形式
完整代码如下
var form = document.getElementById('form'),
warn = document.getElementById('warn');
Function.prototype.before = function(beforeFn){
var self = this;
return function(){
if(beforeFn.apply(this, arguments) === false)
return;
return self.apply(this, arguments);
}
}
var vldStrategy = { //策略对象-验证规则
isNonEmpty: function(value, warnMsg){ //输入不为空
if(value === '')
return warnMsg;
},
isLongEnough: function(value, length, warnMsg){ //输入足够长
if(value.length < length)
return warnMsg;
},
isShortEnough: function(value, length, warnMsg){ //输入足够短
if(value.length > length)
return warnMsg;
},
isMobile: function(value, warnMsg){ //手机号验证
var reg = /^1[3|5|8][0-9]{9}$/;
if(!reg.test(value))
return warnMsg;
}
}
var Validator = function(){ //环境类
this.rules = []; //数组用于存放负责验证的函数
};
Validator.prototype.add = function(domNode, ruleArr){ //添加验证规则
var self = this;
for(var i = 0, rule; rule = ruleArr[i++];){
(function(rule){
var strategyArr = rule.strategy.split(':'),
warnMsg = rule.warnMsg;
self.rules.push(function(){
var tempArr = strategyArr.concat();
var ruleName = tempArr.shift();
tempArr.unshift(domNode.value);
tempArr.push(warnMsg);
return vldStrategy[ruleName].apply(domNode, tempArr);
});
})(rule);
}
return this;
};
Validator.prototype.start = function(){ //开始验证表单
for(var i = 0, vldFn; vldFn = this.rules[i++];){
var warnMsg = vldFn();
if(warnMsg){
warn.textContent = warnMsg;
return false;
}
}
}
var vld = new Validator();
vld.add(form.username, [
{
strategy: 'isNonEmpty',
warnMsg: '账号不能为空'
},
{
strategy: 'isLongEnough:4',
warnMsg: '账号不能小于4位'
},
{
strategy: 'isShortEnough:20',
warnMsg: '账号不能大于20位'
}
]).add(form.password, [
{
strategy: 'isNonEmpty',
warnMsg: '密码不能为空'
}
]).add(form.phonenum, [
{
strategy: 'isNonEmpty',
warnMsg: '手机号不能为空'
},
{
strategy: 'isMobile',
warnMsg: '手机号格式不正确'
}
]);
var submitMsg = function(){
var msg = {
username: form.username.value,
password: form.password.value,
phonenum: form.phonenum.value
}
//ajax('...', msg);
return warn.textContent = '用户信息已成功提交至服务器';
}
submitMsg = submitMsg.before(vld.start.bind(vld));
form.submit.onclick = function(){
submitMsg();
};
//这里只是模拟提交，实际应该用form.onsubmit
</div>
问题分析
总结一下易错的地方还有我敲得时候遇到的问题
Validator.prototype.add = function(domNode, ruleArr){
var self = this;
for(var i = 0, rule; rule = ruleArr[i++];){
(function(rule){
var strategyArr = rule.strategy.split(':'),
warnMsg = rule.warnMsg;
self.rules.push(function(){
var tempArr = strategyArr.concat();
var ruleName = tempArr.shift();
tempArr.unshift(domNode.value);
tempArr.push(warnMsg);
return vldStrategy[ruleName].apply(domNode, tempArr);
});
})(rule);
}
return this;
};
</div>
在Validator原型链上的add函数需要注意几个问题
首先添加IIFE立即执行函数解决闭包问题就不用多说了
函数内又嵌套了函数，导致了this被劫持，所以必须缓存this
var self = this;
最开始我没有拷贝这个数组而是直接使用的strategyArr
Validator.prototype.add = function(domNode, ruleArr){ //添加验证规则
var self = this;
for(var i = 0, rule; rule = ruleArr[i++];){
(function(rul