javascript 图片放大实现源码

			function getEventObject(W3CEvent) {//事件标准化函数return W3CEvent || window.event;}function getPointerPosition(e) {//兼容浏览器的鼠标x,y获得函数e = e || getEventObject(e);var x = e.pageX || (e.clientX + (document.documentElement.scrollLeft || document.body.scrollLeft));var y = e.pageY || (e.clientY + (document.documentElement.scrollTop || document.body.scrollTop));return {'x' : x,'y' : y};}function setOpacity(elem, level) {//兼容浏览器设置透明值if (elem.filters) {elem.style.filter = 'alpha(opacity=' + level * 100 + ')';} else {elem.style.opacity = level;}}function css(elem, prop) {//css设置函数,可以方便设置css值,并且兼容设置透明值for (var i in prop) {if (i == 'opacity') {setOpacity(elem, prop[i]);} else {elem.style[i] = prop[i];}}return elem;}var magnifier = {m : null,init : function(magni) {var m = this.m = magni || {cont : null, //装载原始图像的divimg : null, //放大的图像mag : null, //放大框scale : 15	//比例值,设置的值越大放大越大,但是这里有个问题就是如果不可以整除时,会产生些很小的白边,目前不知道如何解决}css(m.img, {'position' : 'absolute','width' : (m.cont.clientWidth * m.scale) + 'px', //原始图像的宽*比例值'height' : (m.cont.clientHeight * m.scale) + 'px'	//原始图像的高*比例值})css(m.mag, {'display' : 'none','width' : m.cont.clientWidth + 'px', //m.cont为原始图像,与原始图像等宽'height' : m.cont.clientHeight + 'px','position' : 'absolute','left' : m.cont.offsetLeft + m.cont.offsetWidth + 10 + 'px', //放大框的位置为原始图像的右方远10px'top' : m.cont.offsetTop + 'px'})var borderWid = m.cont.getElementsByTagName('div')[0].offsetWidth - m.cont.getElementsByTagName('div')[0].clientWidth;//获取border的宽css(m.cont.getElementsByTagName('div')[0], {//m.cont.getElementsByTagName('div')[0]为浏览框'display' : 'none', //开始设置为不可见'width' : m.cont.clientWidth / m.scale - borderWid + 'px', //原始图片的宽/比例值 - border的宽度'height' : m.cont.clientHeight / m.scale - borderWid + 'px', //原始图片的高/比例值 - border的宽度'opacity' : 0.5//设置透明度})m.img.src = m.cont.getElementsByTagName('img')[0].src;//让原始图像的src值给予放大图像m.cont.style.cursor = 'crosshair';m.cont.onmouseover = magnifier.start;},start : function(e) {if (document.all) {//只在IE下执行,主要避免IE6的select无法覆盖magnifier.createIframe(magnifier.m.img);}this.onmousemove = magnifier.move;//this指向m.contthis.onmouseout = magnifier.end;},move : function(e) {var pos = getPointerPosition(e);//事件标准化this.getElementsByTagName('div')[0].style.display = '';css(this.getElementsByTagName('div')[0], {'top' : Math.min(Math.max(pos.y - this.offsetTop - parseInt(this.getElementsByTagName('div')[0].style.height) / 2, 0), this.clientHeight - this.getElementsByTagName('div')[0].offsetHeight) + 'px','left' : Math.min(Math.max(pos.x - this.offsetLeft - parseInt(this.getElementsByTagName('div')[0].style.width) / 2, 0), this.clientWidth - this.getElementsByTagName('div')[0].offsetWidth) + 'px'	//left=鼠标x - this.offsetLeft - 浏览框宽/2,Math.max和Math.min让浏览框不会超出图像})magnifier.m.mag.style.display = '';css(magnifier.m.img, {'top' : -(parseInt(this.getElementsByTagName('div')[0].style.top) * magnifier.m.scale) + 'px','left' : -(parseInt(this.getElementsByTagName('div')[0].style.left) * magnifier.m.scale) + 'px'})},end : function(e) {this.getElementsByTagName('div')[0].style.display = 'none';magnifier.removeIframe(magnifier.m.img);//销毁iframemagnifier.m.mag.style.display = 'none';},createIframe : function(elem) {var layer = document.createElement('iframe');layer.tabIndex = '-1';layer.src = 'javascript:false;';elem.parentNode.appendChild(layer);layer.style.width = elem.offsetWidth + 'px';layer.style.height = elem.offsetHeight + 'px';},removeIframe : function(elem) {var layers = elem.parentNode.getElementsByTagName('iframe');while (layers.length > 0) {layers[0].parentNode.removeChild(layers[0]);}}}