本文实例讲述了javaScript实现可缩放的显示区效果代码。分享给大家供大家参考，具体如下：
这里演示可缩放的显示区，采用JS代码实现，鼠标按住区域的右下角，出现拖放箭头时，向下或向上拉，就可实现缩放操作，当区域较小时显示滚动条，平时也比较常见的效果，在此将JavaScript代码与大家分享。
运行效果截图如下：
在线演示地址如下：
http://demo.jb51.net/js/2015/js-ksf-box-style-demo/
具体代码如下：
<HTML> <HEAD> <TITLE>可缩放的显示区</TITLE> <STYLE type=text/css> BODY { MARGIN-TOP: 0px; FONT-SIZE: 9pt; MARGIN-LEFT: 0px; MARGIN-RIGHT: 0px; FONT-FAMILY: "宋体" } A { FONT-WEIGHT: 400; FONT-SIZE: 9pt; COLOR: black; TEXT-DECORATION: none } A:hover { FONT-WEIGHT: 400; FONT-SIZE: 9pt; COLOR: red; TEXT-DECORATION: underline } A:active { FONT: 9pt "宋体"; CURSOR: hand; COLOR: #ff0033 } .STYLE1 {font-family: "华文彩云", "华文仿宋", "华文细黑", "华文新魏", "华文行楷", "华文中宋", "新宋体", "幼圆"} .STYLE2 { font-family: "方正姚体"; font-weight: bold; } </STYLE> <META http-equiv=Content-Type content="text/html; charset=gb2312"> </HEAD> <BODY bgColor=#fef4d9> <CENTER> <span><FONT color=black size=16>可缩放的显示区</FONT></span> </CENTER><BR> <CENTER> <TABLE borderColor=#00FF00 border=5 borderlight="green"> <TBODY> <TR> <TD align=left> <STYLE>UNKNOWN { box-sizing: border-box; moz-box-sizing: border-box } #testDiv { BORDER-RIGHT: white 2px outset; PADDING-RIGHT: 2px; BACKGROUND-POSITION: 0% 50%; BORDER-TOP: white 2px outset; PADDING-LEFT: 2px; Z-INDEX: 2; BACKGROUND-ATTACHMENT: scroll; LEFT: 30px; PADDING-BOTTOM: 2px; MARGIN: 0px; OVERFLOW: hidden; BORDER-LEFT: white 2px outset; WIDTH: 500px; COLOR: #3969a5; PADDING-TOP: 2px; BORDER-BOTTOM: white 2px outset; BACKGROUND-REPEAT: repeat; HEIGHT: 300px; BACKGROUND-COLOR: buttonface } BODY { FONT-SIZE: 9pt; FONT-FAMILY: Verdana } #innerNice { BORDER-RIGHT: white 2px inset; PADDING-RIGHT: 8px; BACKGROUND-POSITION: 0% 50%; BORDER-TOP: white 2px inset; PADDING-LEFT: 8px; BACKGROUND-ATTACHMENT: scroll; PADDING-BOTTOM: 8px; OVERFLOW: auto; BORDER-LEFT: white 2px inset; WIDTH: 100%; COLOR: #3969a5; PADDING-TOP: 8px; BORDER-BOTTOM: white 2px inset; BACKGROUND-REPEAT: repeat; HEIGHT: 100%; BACKGROUND-COLOR: white } </STYLE> <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> <SCRIPT language=javascript> var theobject = null; //This gets a value as soon as a resize start function resizeObject() { this.el = null; //pointer to the object this.dir = ""; //type of current resize (n, s, e, w, ne, nw, se, sw) this.grabx = null; //Some useful values this.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 pixels if (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 possible yMin = 8; // height el = getReal(event.srcElement, "className", "resizeMe"); if (el.className == "resizeMe") { str = getDirection(el); //Fix the cursor if (str == "") str = "default"; else str += "-resize"; el.style.cursor = str; } //Dragging starts here if(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> </TD></TR></TBODY></TABLE> </CENTER> </BODY> </HTML>
希望本文所述对大家JavaScript程序设计有所帮助。