原文 http://www.cnblogs.com/GongQi/p/4074609.html?utm_source=tuicool&utm_medium=referral
<script>
//1.基本原理
//頁面加載後,通過javascript建立頁面元素div,并在div元素中建立文本節點,展示水印内容
//設定div元素樣式,将其zIndex設定一個較高的值,并設定透明度,實作浮在頁面的水印效果
//其核心邏輯如下所示
var mask_div = document.createElement('div');
mask_div.id = 'mask_div1';
mask_div.appendChild(document.createTextNode(""));
mask_div.style.position = "absolute";
mask_div.style.left = '20px';
mask_div.style.top = '20px';
mask_div.style.overflow = "hidden";
mask_div.style.zIndex = "9999";
mask_div.style.opacity = 0.3;
document.body.appendChild(mask_div);
//2.繼續完善
//上述示例隻在頁面某處展示了一個水印,實際應用中往往需要在頁面中鋪滿水印
//在滿足這種需求同時,下述代碼将各種屬性以配置方式提供給使用者,可根據需要靈活調用
function watermark(settings) {
//預設設定
var defaultSettings={
watermark_txt:"", // 預設的水印字
watermark_x:20,//水印起始位置x軸坐标
watermark_y:20,//水印起始位置Y軸坐标
watermark_rows:20,//水印行數
watermark_cols:20,//水印列數
watermark_x_space:100,//水印x軸間隔
watermark_y_space:50,//水印y軸間隔
watermark_color:'#000000',//水印字型顔色
watermark_alpha:0.3,//水印透明度
watermark_fontsize:'18px',//水印字型大小
watermark_font:'微軟雅黑',//水印字型
watermark_width:120,//水印寬度
watermark_height:80,//水印長度
watermark_angle:15//水印傾斜度數
};
//采用配置項替換預設值,作用類似jquery.extend
if(arguments.length===1&&typeof arguments[0] ==="object" )
{
var src=arguments[0]||{};
for(key in src)
{
if(src[key]&&defaultSettings[key]&&src[key]===defaultSettings[key])
continue;
else if(src[key])
defaultSettings[key]=src[key];
}
}
var oTemp = document.createDocumentFragment();
//擷取頁面最大寬度
var page_width = Math.max(document.body.scrollWidth,document.body.clientWidth);
//擷取頁面最大長度
var page_height = Math.max(document.body.scrollHeight,document.body.clientHeight);
//如果将水印列數設定為0,或水印列數設定過大,超過頁面最大寬度,則重新計算水印列數和水印x軸間隔
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)) {
defaultSettings.watermark_cols =
parseInt((page_width
-defaultSettings.watermark_x
+defaultSettings.watermark_x_space)
/ (defaultSettings.watermark_width
+ defaultSettings.watermark_x_space));
defaultSettings.watermark_x_space =
parseInt((page_width
- defaultSettings.watermark_x
- defaultSettings.watermark_width
* defaultSettings.watermark_cols)
/ (defaultSettings.watermark_cols - 1));
}
//如果将水印行數設定為0,或水印行數設定過大,超過頁面最大長度,則重新計算水印行數和水印y軸間隔
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)) {
defaultSettings.watermark_rows =
parseInt((defaultSettings.watermark_y_space
+ page_height - defaultSettings.watermark_y)
/ (defaultSettings.watermark_height + defaultSettings.watermark_y_space));
defaultSettings.watermark_y_space =
parseInt((page_height
- defaultSettings.watermark_y
- defaultSettings.watermark_height
* defaultSettings.watermark_rows)
/ (defaultSettings.watermark_rows - 1));
}
var x;
var y;
for (var i = 0; i < defaultSettings.watermark_rows; i++) {
y = defaultSettings.watermark_y + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i;
for (var j = 0; j < defaultSettings.watermark_cols; j++) {
x = defaultSettings.watermark_x + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j;
var mask_div = document.createElement('div');
mask_div.id = 'mask_div' + i + j;
mask_div.appendChild(document.createTextNode(defaultSettings.watermark_txt));
//設定水印div傾斜顯示
mask_div.style.webkitTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
mask_div.style.MozTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
mask_div.style.msTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
mask_div.style.OTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
mask_div.style.transform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
mask_div.style.visibility = "";
mask_div.style.position = "absolute";
mask_div.style.left = x + 'px';
mask_div.style.top = y + 'px';
mask_div.style.overflow = "hidden";
mask_div.style.zIndex = "9999";
//mask_div.style.;
mask_div.style.opacity = defaultSettings.watermark_alpha;
mask_div.style.fontSize = defaultSettings.watermark_fontsize;
mask_div.style.fontFamily = defaultSettings.watermark_font;
mask_div.style.color = defaultSettings.watermark_color;
mask_div.style.textAlign = "center";
mask_div.style.width = defaultSettings.watermark_width + 'px';
mask_div.style.height = defaultSettings.watermark_height + 'px';
mask_div.style.display = "block";
oTemp.appendChild(mask_div);
};
};
document.body.appendChild(oTemp);
// 調用方式
// watermark({ watermark_txt: "測試水印" })//傳入動态水印内容
//onload時觸發水印繪制
//window.onload=function(){
//watermark({ watermark_txt: "測試水印" });
//};
//onresize時觸發水印繪制
//window.onresize = function () {
//watermark({ watermark_txt: "測試水印",watermark_width:50 })
//};
}
</script>
ps:<body οncοntextmenu=self.event.returnValue=false onselectstart="return false"> 加上這個防止另存為圖檔