之前有個項目做完給用戶演示的時候，界面上加了水印效果，今天把具體實現的方法分享一下。
首先看下效果：
核心js代碼（shuiyin.js）：
1 function watermark(settings) { 2 //默認設置 3 var defaultSettings = { 4 watermark_txt: "text", 5 watermark_x: 20, //水印起始位置x軸坐標 6 watermark_y: 20, //水印起始位置Y軸坐標 7 watermark_rows: 20, //水印行數 8 watermark_cols: 20, //水印列數 9 watermark_x_space: 100, //水印x軸間隔 10 watermark_y_space: 50, //水印y軸間隔 11 watermark_color: '#aaa', //水印字體顏色 12 watermark_alpha: 0.4, //水印透明度 13 watermark_fontsize: '15px', //水印字體大小 14 watermark_font: '微軟雅黑', //水印字體 15 watermark_width: 210, //水印寬度 16 watermark_height: 80, //水印長度 17 watermark_angle: 20 //水印傾斜度數 18 }; 19 if (arguments.length === 1 && typeof arguments[0] === "object") { 20 var src = arguments[0] || {}; 21 for (key in src) { 22 if (src[key] && defaultSettings[key] && src[key] === defaultSettings[key]) continue; 23 else if (src[key]) defaultSettings[key] = src[key]; 24 } 25 } 26 var oTemp = document.createDocumentFragment(); 27 //獲取頁面最大寬度 28 var page_width = Math.max(document.body.scrollWidth, document.body.clientWidth); 29 var cutWidth = page_width * 0.0150; 30 var page_width = page_width - cutWidth; 31 //獲取頁面最大高度 32 var page_height = Math.max(document.body.scrollHeight, document.body.clientHeight) + 450; 33 page_height = Math.max(page_height, window.innerHeight - 30); 34 //如果將水印列數設置為0，或水印列數設置過大，超過頁面最大寬度，則重新計算水印列數和水印x軸間隔 35 if (defaultSettings.watermark_cols == 0 || (parseInt(defaultSettings.watermark_x + defaultSettings.watermark_width * defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)) > page_width)) { 36 defaultSettings.watermark_cols = parseInt((page_width - defaultSettings.watermark_x + defaultSettings.watermark_x_space) / (defaultSettings.watermark_width + defaultSettings.watermark_x_space)); 37 defaultSettings.watermark_x_space = parseInt((page_width - defaultSettings.watermark_x - defaultSettings.watermark_width * defaultSettings.watermark_cols) / (defaultSettings.watermark_cols - 1)); 38 } 39 //如果將水印行數設置為0，或水印行數設置過大，超過頁面最大長度，則重新計算水印行數和水印y軸間隔 40 if (defaultSettings.watermark_rows == 0 || (parseInt(defaultSettings.watermark_y + defaultSettings.watermark_height * defaultSettings.watermark_rows + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)) > page_height)) { 41 defaultSettings.watermark_rows = parseInt((defaultSettings.watermark_y_space + page_height - defaultSettings.watermark_y) / (defaultSettings.watermark_height + defaultSettings.watermark_y_space)); 42 defaultSettings.watermark_y_space = parseInt(((page_height - defaultSettings.watermark_y) - defaultSettings.watermark_height * defaultSettings.watermark_rows) / (defaultSettings.watermark_rows - 1)); 43 } 44 var x; 45 var y; 46 for (var i = 0; i < defaultSettings.watermark_rows; i++) { 47 y = defaultSettings.watermark_y + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i; 48 for (var j = 0; j < defaultSettings.watermark_cols; j++) { 49 x = defaultSettings.watermark_x + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j; 50 var mask_div = document.createElement('div'); 51 mask_div.id = 'mask_div' + i + j; 52 mask_div.className = 'mask_div'; 53 mask_div.appendChild(document.createTextNode(defaultSettings.watermark_txt)); 54 //設置水印div傾斜顯示 55 mask_div.style.webkitTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)"; 56 mask_div.style.MozTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)"; 57 mask_div.style.msTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)"; 58 mask_div.style.OTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)"; 59 mask_div.style.transform = "rotate(-" + defaultSettings.watermark_angle + "deg)"; 60 mask_div.style.visibility = ""; 61 mask_div.style.position = "absolute"; 62 mask_div.style.left = x + 'px'; 63 mask_div.style.top = y + 'px'; 64 mask_div.style.overflow = "hidden"; 65 mask_div.style.zIndex = "9999"; 66 //讓水印不遮擋頁面的點擊事件 67 mask_div.style.pointerEvents = 'none'; 68 mask_div.style.opacity = defaultSettings.watermark_alpha; 69 mask_div.style.fontSize = defaultSettings.watermark_fontsize; 70 mask_div.style.fontFamily = defaultSettings.watermark_font; 71 mask_div.style.color = defaultSettings.watermark_color; 72 mask_div.style.textAlign = "center"; 73 mask_div.style.width = defaultSettings.watermark_width + 'px'; 74 mask_div.style.height = defaultSettings.watermark_height + 'px'; 75 mask_div.style.display = "block"; 76 oTemp.appendChild(mask_div); 77 }; 78 }; 79 document.body.appendChild(oTemp); 80 } 81 82 function getNow() { 83 var d = new Date(); 84 var year = d.getFullYear(); 85 var month = change(d.getMonth() + 1); 86 var day = change(d.getDate()); 87 var hour = change(d.getHours()); 88 var minute = change(d.getMinutes()); 89 var second = change(d.getSeconds()); 90 91 function change(t) { 92 if (t < 10) { 93 return "0" + t; 94 } else { 95 return t; 96 } 97 } 98 var time = year + '年' + month + '月' + day + '日 ' + hour + '時' + minute + '分' + second + '秒'; 99 return time; 100 }
調用方法：
在html中引入jquery.js，shuiyin.js，然后使用以下代碼調用：
watermark({ "watermark_txt": "水印文字內容"});
本文最開始預覽效果的調用方式如下（不包含html部分，html無要求）：
1 var now = getNow(); 2 watermark({ "watermark_txt": "樣稿" + now });