本文实例讲述了javascript实现鼠标拖动改变层大小的方法。分享给大家供大家参考。具体实现方法如下：
<html><head><title>拖动改变层的大小</title><meta content="text/html; charset=gb2312" http-equiv="Content-Type"><style> {box-sizing: border-box; moz-box-sizing: border-box}#testDiv { background-color: buttonface; background-repeat: repeat; background-attachment: scroll; color: #3969A5; height: 300px; left: 30px; overflow: hidden; width: 500; z-index: 2; border: 2px outset white; margin: 0px; padding: 2px; background-position: 0% 50% }body { font-family: Verdana; font-size: 9pt }#innerNice { background-color: white; background-repeat: repeat;background-attachment: scroll; color: #3969A5; height: 100%; overflow: auto; width: 100%; border: 2px inset white; padding: 8px; background-position: 0% 50% }</style><SCRIPT language=javascript>var theobject = null; function resizeObject() {this.el = null; //pointer to the objectthis.dir = ""; //type of current resize (n,s,e,w,ne,nw,se,sw)this.grabx = null; //Some useful valuesthis.graby = null;this.width = null;this.height = null;this.left = null;this.top = null;}function getDirection(el) {var xPos, yPos, offset, dir;dir = "";xPos = window.event.offsetX;yPos = window.event.offsetY;offset = 8; //The distance from the edge in pixelsif (yPos<offset) dir += "n";else if (yPos > el.offsetHeight-offset) dir += "s";if (xPos<offset) dir += "w";else if (xPos > el.offsetWidth-offset) dir += "e";return dir;}function doDown() {var el = getReal(event.srcElement, "className", "resizeMe");if (el == null) {theobject = null;return;} dir = getDirection(el);if (dir == "") return;theobject = new resizeObject();theobject.el = el;theobject.dir = dir;theobject.grabx = window.event.clientX;theobject.graby = window.event.clientY;theobject.width = el.offsetWidth;theobject.height = el.offsetHeight;theobject.left = el.offsetLeft;theobject.top = el.offsetTop;window.event.returnValue = false;window.event.cancelBubble = true;}function doUp() {if (theobject != null) {theobject = null;}}function doMove() {var el, xPos, yPos, str, xMin, yMin;xMin = 8; //The smallest width possibleyMin = 8; // heightel = getReal(event.srcElement, "className", "resizeMe");if (el.className == "resizeMe") {str = getDirection(el);//Fix the cursorif (str == "") str = "default";else str += "-resize";el.style.cursor = str;}//Dragging starts hereif(theobject != null) {if (dir.indexOf("e") != -1)theobject.el.style.width = Math.max(xMin, theobject.width + window.event.clientX - theobject.grabx) + "px";if (dir.indexOf("s") != -1)theobject.el.style.height = Math.max(yMin, theobject.height + window.event.clientY - theobject.graby) + "px";if (dir.indexOf("w") != -1) {theobject.el.style.left = Math.min(theobject.left + window.event.clientX - theobject.grabx, theobject.left + theobject.width - xMin) + "px";theobject.el.style.width = Math.max(xMin, theobject.width - window.event.clientX + theobject.grabx) + "px";}if (dir.indexOf("n") != -1) {theobject.el.style.top = Math.min(theobject.top + window.event.clientY - theobject.graby, theobject.top + theobject.height - yMin) + "px";theobject.el.style.height = Math.max(yMin, theobject.height - window.event.clientY + theobject.graby) + "px";}window.event.returnValue = false;window.event.cancelBubble = true;} }function getReal(el, type, value) {temp = el;while ((temp != null) && (temp.tagName != "BODY")) {if (eval("temp." + type) == value) {el = temp;return el;}temp = temp.parentElement;}return el;}document.onmousedown = doDown;document.onmouseup = doUp;document.onmousemove = doMove;</SCRIPT></head><body><div class="resizeMe" id="testDiv"><div id="innerNice"><p align="center"> </p><p align="center">请在边框处拖动鼠标</p><p> </p><p> </p><p> </p></div></div></body></html>希望本文所述对大家的javascript程序设计有所帮助。
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