文實例講述了javascript實現鼠標拖動改變層大小的方法。分享給大家供大家參考。具體實現方法如下：
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 <html> <head> <title>拖動改變層的大小</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 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> </head> <body> <div class="resizeMe" id="testDiv"> <div id="innerNice"> <p align="center"> </p> <p align="center"> 請在邊框處拖動鼠標</p> <p> </p> <p> </p> <p> </p> </div> </div> </body> </html>希望本文所述對大家的javascript程序設計有所幫助。