<!DOCTYPE html>
<html>
<!-- head -->
<head>
<meta charset="utf-8">
<title>Image login verification</title>
<meta name="renderer" content="webkit">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<style>
body{margin: 10px;}
.demo-carousel{height: 200px; line-height: 200px; text-align: center;}
.code {
width: 400px;
margin: 0 auto;
}
.input-val {
width: 295px;
background: #ffffff;
height: 2.8rem;
padding: 0 2%;
border-radius: 5px;
border: none;
border: 1px solid rgba(0,0,0,.2);
font-size: 1.0625rem;
}
#canvas {
float: right;
display: inline-block;
border: 1px solid #ccc;
border-radius: 5px;
cursor: pointer;
}
.btn {
width: 100px;
height: 40px;
background: #f1f1f1;
border: 1px solid #ccc;
border-radius: 5px;
margin: 20px auto 0;
display: block;
font-size: 1.2rem;
color: #e22e1c;
cursor: pointer;
}
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
</style>
</head>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<body cz-shortcut-listen="true" class="layui-layout-body">
<div class="layui-layer-move">
<div class="code">
<input type="text" value="" placeholder="Please enter the verification code (case insensitive)" class ="input-val">
<canvas id="canvas" width="100" height="43"></canvas>
<button class="btn">提交</button>
</div>
</div>
</body>
<script>
$(function(){
var show_num = [];
draw(show_num);
$("#canvas").on('click',function(){
draw(show_num);
})
$(".btn").on('click',function(){
var val = $(".input-val").val().toLowerCase();
var num = show_num.join("");
if(val==''){
alert( 'Please enter the verification code!' );
}else if(val == num){
alert( 'Submission successful!' );
$(".input-val").val('');
draw(show_num);
}else{
alert( 'Verification code error! Please re-enter!' );
$(".input-val").val('');
draw(show_num);
}
})
})
function draw(show_num) {
var canvas_width=$('#canvas').width();
var canvas_height=$('#canvas').height();
var canvas = document.getElementById("canvas"); // Get the canvas object, the actor
var context = canvas.getContext("2d"); // Get the canvas drawing environment, the stage where the actor performs
canvas.width = canvas_width;
canvas.height = canvas_height;
var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
var aCode = sCode.split(",");
var aLength = aCode.length; // Get the length of the array
for (var i = 0; i <= 3; i++) {
var j = Math.floor(Math.random() * aLength); // Get a random index value
var deg = Math.random() * 30 * Math.PI / 180; // Generate between 0~30 Random radian
var txt = aCode[j]; // Get a random content
show_num[i] = txt.toLowerCase();
var x = 10 + i * 20; // the x coordinate of the text on the canvas
var y = 20 + Math.random() * 8; // the y coordinate of the text on the canvas
context.font = "bold 23px Microsoft Yahei " ;
context.translate(x, y);
context.rotate(deg);
context.fillStyle = randomColor();
context.fillText(txt, 0, 0);
context.rotate(-deg);
context.translate(-x, -y);
}
for (var i = 0; i <= 5; i++) { // Display lines on the verification code
context.strokeStyle = randomColor();
context.beginPath();
context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
context.stroke();
}
for (var i = 0; i <= 30; i++) { // A small dot is displayed on the verification code
context.strokeStyle = randomColor();
context.beginPath();
var x = Math.random() * canvas_width;
var y = Math.random() * canvas_height;
context.moveTo(x, y);
context.lineTo(x + 1, y + 1 );
context.stroke();
}
}
function randomColor() { // Get a random color value
var r = Math.floor(Math.random() * 256 );
var g = Math.floor(Math.random() * 256);
var b = Math.floor(Math.random() * 256);
return "rgb(" + r + "," + g + "," + b + ")";
}
</script>
</html>
You can also use the back-end verification method
https://blog.csdn.net/datuo/article/details/1393227
https://blog.csdn.net/rchm8519/article/details/45081225
package com.hikvision.cms.module.cpi.servlet; import java.awt.Color; import java.awt.Container; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.util.Random; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; public class ImageTool { public String sRand = ""; public Color getRandColor(int fc, int bc) { // Get a random color for a given range Random random = new Random(); if (fc > 255 ) fc = 255; if (bc > 255) bc = 255; int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); } public BufferedImage creatImage() { // Create image in memory int width = 60 ; int height = 20 ; BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); // Get graphics context Graphics g = image.getGraphics(); // Generate random class Random random = new Random(); // Set the background color g.setColor(getRandColor(200,250 )); g.fillRect(0, 0, width, height); // Set the font g.setFont( new Font("Times New Roman",Font.PLAIN,18 )); // Draw a border // g.setColor(new Color()); // g.drawRect(0, 0, width-1, height-1); // Randomly generate 155 interference lines to make the authentication code in the image Not easily detectable by other programs for ( int i=0; i<155; i++ ) { g.setColor(getRandColor(160,200)); int x = random.nextInt(width); int y = random.nextInt(height); int x1 = random.nextInt(12); int y1 = random.nextInt(12); g.drawLine(x, y, x+x1, y+y1); } // Take the randomly generated authentication code (4 digits) sRand = "" ; for ( int i=0; i<4; i++ ) { String rand = String .valueOf(random.nextInt(10)); sRand += rand; // Display the authentication code in the image g.setColor ( new Color(20+random.nextInt(110), 20 + random.nextInt(110), 20+random.nextInt(110 ))); // The color from calling the function is the same, maybe because the seeds are too close, so we can only directly generate g.drawString(rand, 13*i+6, 16 ); } // The image takes effect g.dispose(); return image; } public String getRand() { return sRand; } public static void main(String[] args) { ImageTool it = new ImageTool(); JFrame jf = new JFrame(); jf.setSize ( 200,300 ); jf.setTitle( "Generate verification code" ); Container ct = jf.getContentPane(); ImageIcon ii = new ImageIcon(it.creatImage()); JLabel jl = new JLabel(ii); ct.add(jl); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.setVisible(true); System.out.println(it.getRand()); } }