图片随意移动，可以拖动图片

最新推荐文章于 2022-03-03 16:54:16 发布

转载最新推荐文章于 2022-03-03 16:54:16 发布 · 3.8k 阅读

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#ie #function #javascript #web开发 #variables #null

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本文介绍了一种实现网页中图片随意拖动的技术方案。通过JavaScript编程，可以使页面上的图片响应用户的鼠标操作，实现自由移动的效果。适用于早期浏览器环境，如Netscape和IE。

<HTML> <HEAD> <META http-equiv='Content-Type' content='text/html; charset=gb2312'> <TITLE>图片随意移动，可以拖动图片</TITLE> </HEAD> <BODY bgcolor="#fef4d9" onLoad="init()"> <mce:style type="text/css"></mce:style><style type="text/css" mce_bogus="1"> #plane1 {position:absolute; left:290; top:170; width:121; z-index:0} #plane2 {position:absolute; left:400; top:250; width:118; z-index:0}</style> <SCRIPT LANGUAGE="JavaScript"> //Modified by the CoffeeCup HTML Editor++ //http://www.coffeecup.com // Global variables for platform branching var isNav, isIE if (parseInt(navigator.appVersion) >= 4) { if (navigator.appName == "Netscape") { isNav = true } else { isIE = true } } // ***Begin CSS custom API Functions*** // Set zIndex property function setZIndex(obj, zOrder) { obj.zIndex = zOrder } // Position an object at a specific pixel coordinate function shiftTo(obj, x, y) { if (isNav) { obj.moveTo(x,y) } else { obj.pixelLeft = x obj.pixelTop = y } } // ***End API Functions*** // Global holds reference to selected element var selectedObj // Globals hold location of click relative to element var offsetX, offsetY // Find out which element has been clicked on function setSelectedElem(evt) { if (isNav) { // declare local var for use in upcoming loop var testObj // make copies of event coords for use in upcoming loop var clickX = evt.pageX var clickY = evt.pageY // loop through all layers (starting with frontmost layer) // to find if the event coordinates are in the layer for (var i = document.layers.length - 1; i >= 0; i--) { testObj = document.layers[i] if ((clickX > testObj.left) && (clickX < testObj.left + testObj.clip.width) && (clickY > testObj.top) && (clickY < testObj.top + testObj.clip.height)) { // if so, then set the global to the layer, bring it // forward, and get outa here selectedObj = testObj setZIndex(selectedObj, 100) return } } } else { // use IE event model to get the targeted element var imgObj = window.event.srcElement // make sure it's one of our planes if (imgObj.parentElement.id.indexOf("plane") != -1) { // then set the global to the style property of the element, // bring it forward, and say adios selectedObj = imgObj.parentElement.style setZIndex(selectedObj,100) return } } // the user probably clicked on the background selectedObj = null return } // Drag an element function dragIt(evt) { // operate only if a plane is selected if (selectedObj) { if (isNav) { shiftTo(selectedObj, (evt.pageX - offsetX), (evt.pageY - offsetY)) } else { shiftTo(selectedObj, (window.event.clientX - offsetX), (window.event.clientY - offsetY)) // prevent further system response to dragging in IE return false } } } // Set globals to connect with selected element function engage(evt) { setSelectedElem(evt) if (selectedObj) { // set globals that remember where the click is in relation to the // top left corner of the element so we can keep the element-to-cursor // relationship constant throughout the drag if (isNav) { offsetX = evt.pageX - selectedObj.left offsetY = evt.pageY - selectedObj.top } else { offsetX = window.event.offsetX offsetY = window.event.offsetY } } // block mouseDown event from forcing Mac to display // contextual menu. return false } // Restore elements and globals to initial values function release(evt) { if (selectedObj) { setZIndex(selectedObj, 0) selectedObj = null } } // Turn on event capture for Navigator function setNavEventCapture() { if (isNav) { document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP) } } // Assign event handlers used by both Navigator and IE (called by onLoad) function init() { if (isNav) { setNavEventCapture() } // assign functions to each of the events (works for both Navigator and IE) document.onmousedown = engage document.onmousemove = dragIt document.onmouseup = release } </SCRIPT> <DIV ID=plane1><IMG NAME="planePic1" SRC="http://www.webasp.net/images/logo.gif" mce_SRC="http://www.webasp.net/images/logo.gif" BORDER=0></DIV> <DIV ID=plane2><IMG NAME="planePic1" SRC="http://www.webasp.net/images/logos.gif" mce_SRC="http://www.webasp.net/images/logos.gif" BORDER=0></DIV> </BODY></HTML>

(from:http://www.webasp.net/javascript/1/250.htm)

<HTML> <HEAD> <META http-equiv='Content-Type' content='text/html; charset=gb2312'> <TITLE>页面上可以用鼠标拖动的图片</TITLE> <mce:style type="text/css"></mce:style><style type="text/css" mce_bogus="1">#floater { position: absolute; left: 500; top: 146; width: 125; visibility: visible; z-index: 10; }</style> </HEAD> <BODY > <div ID="floater" style="left: 590px; top: 158px"> <p align="center"><img SRC="http://www.webasp.net/images/logo.gif" mce_SRC="http://www.webasp.net/images/logo.gif" alt="中国WEB开发者网络"><br> <font color="#FF8040">中国WEB开发者网络</font></p> </div><mce:script LANGUAGE="JavaScript"> function heartBeat() { if(IE) { diffY = document.body.scrollTop; diffX = document.body.scrollLeft; } if(NS) { diffY = self.pageYOffset; diffX = self.pageXOffset; } if(diffY != lastScrollY) { percent = .1 * (diffY - lastScrollY); if(percent > 0) percent = Math.ceil(percent); else percent = Math.floor(percent); if(IE) document.all.floater.style.pixelTop += percent; if(NS) document.floater.top += percent; lastScrollY = lastScrollY + percent; } if(diffX != lastScrollX) { percent = .1 * (diffX - lastScrollX); if(percent > 0) percent = Math.ceil(percent); else percent = Math.floor(percent); if(IE) document.all.floater.style.pixelLeft += percent; if(NS) document.floater.left += percent; lastScrollX = lastScrollX + percent; } }   function checkFocus(x,y) { stalkerx = document.floater.pageX; stalkery = document.floater.pageY; stalkerwidth = document.floater.clip.width; stalkerheight = document.floater.clip.height; if( (x > stalkerx && x < (stalkerx+stalkerwidth)) && (y > stalkery && y < (stalkery+stalkerheight))) return true; else return false; } function grabIt(e) { if(IE) { whichIt = event.srcElement; while (whichIt.id.indexOf("floater") == -1) { whichIt = whichIt.parentElement; if (whichIt == null) { return true; } } whichIt.style.pixelLeft = whichIt.offsetLeft; whichIt.style.pixelTop = whichIt.offsetTop; currentX = (event.clientX + document.body.scrollLeft); currentY = (event.clientY + document.body.scrollTop); } else { window.captureEvents(Event.MOUSEMOVE); if(checkFocus (e.pageX,e.pageY)) { whichIt = document.floater; StalkerTouchedX = e.pageX-document.floater.pageX; StalkerTouchedY = e.pageY-document.floater.pageY; } } return true; } function moveIt(e) { if (whichIt == null) { return false; } if(IE) { newX = (event.clientX + document.body.scrollLeft); newY = (event.clientY + document.body.scrollTop); distanceX = (newX - currentX); distanceY = (newY - currentY); currentX = newX; currentY = newY; whichIt.style.pixelLeft += distanceX; whichIt.style.pixelTop += distanceY; if(whichIt.style.pixelTop < document.body.scrollTop) whichIt.style.pixelTop = document.body.scrollTop; if(whichIt.style.pixelLeft < document.body.scrollLeft) whichIt.style.pixelLeft = document.body.scrollLeft; if(whichIt.style.pixelLeft > document.body.offsetWidth - document.body.scrollLeft - whichIt.style.pixelWidth - 20) whichIt.style.pixelLeft = document.body.offsetWidth - whichIt.style.pixelWidth - 20; if(whichIt.style.pixelTop > document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5) whichIt.style.pixelTop = document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5; event.returnValue = false; } else { whichIt.moveTo(e.pageX-StalkerTouchedX,e.pageY-StalkerTouchedY); if(whichIt.left < 0+self.pageXOffset) whichIt.left = 0+self.pageXOffset; if(whichIt.top < 0+self.pageYOffset) whichIt.top = 0+self.pageYOffset; if( (whichIt.left + whichIt.clip.width) >= (window.innerWidth+self.pageXOffset-17)) whichIt.left = ((window.innerWidth+self.pageXOffset)-whichIt.clip.width)-17; if( (whichIt.top + whichIt.clip.height) >= (window.innerHeight+self.pageYOffset-17)) whichIt.top = ((window.innerHeight+self.pageYOffset)-whichIt.clip.height)-17; return false; } return false; } function dropIt() { whichIt = null; if(NS) window.releaseEvents (Event.MOUSEMOVE); return true; }  if(NS) { window.captureEvents(Event.MOUSEUP|Event.MOUSEDOWN); window.onmousedown = grabIt; window.onmousemove = moveIt; window.onmouseup = dropIt; } if(IE) { document.onmousedown = grabIt; document.onmousemove = moveIt; document.onmouseup = dropIt; } if(NS || IE) action = window.setInterval("heartBeat()",1); // --></mce:script> </BODY></HTML>

(from:http://www.webasp.net/javascript/1/272.htm)