本文實例講述了JavaScript使用面向對象實現的拖拽功能。分享給大家供大家參考，具體如下：
面向對象有個前提：
<!DOCTYPE HTML><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>面向對象的繼承-1</title><style>#div1 {width: 100px; height: 100px; background: red; position: absolute;}</style><script>window.onload = function() { var oDiv = document.getElementById('div1'); oDiv.onmousedown = function(ev) { var ev = ev || event; var disX = ev.clientX - this.offsetLeft; var disY = ev.clientY - this.offsetTop; document.onmousemove = function(ev) { var ev = ev || event; oDiv.style.left = ev.clientX - disX + 'px'; oDiv.style.top = ev.clientY - disY + 'px'; } document.onmouseup = function() { document.onmousemove = document.onmouseup = null; } }}</script></head><body> <div id="div1"></div></body></html>把局部變量改成全局變量
<!DOCTYPE HTML><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>面向對象的繼承-2</title><style>#div1 {width: 100px; height: 100px; background: red; position: absolute;}</style><script>var oDiv=null;var disX=0;var disY=0;window.onload = function() { oDiv = document.getElementById('div1'); oDiv.onmousedown = fnDown;}function fnMove(ev) { var ev = ev || event; oDiv.style.left = ev.clientX - disX + 'px'; oDiv.style.top = ev.clientY - disY + 'px';}function fnUp() { document.onmousemove = document.onmouseup = null;}function fnDown(ev) { var ev = ev || event; disX = ev.clientX - this.offsetLeft; disY = ev.clientY - this.offsetTop; document.onmousemove = fnMove; document.onmouseup =fnUp;}</script></head><body> <div id="div1"></div></body></html>引用塊內容
<!DOCTYPE HTML><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>面向對象的繼承-2</title><style>#div1 {width: 100px; height: 100px; background: red; position: absolute;}#div2 {width: 100px; height: 100px; background: red; position: absolute;top:120px;}</style><script>window.onload=function(){ new Drag('div1'); new Drag('div2');}function Drag(id) { var _this=this; this.disX=0; this.disY=0; this.oDiv = document.getElementById(id); this.oDiv.onmousedown = function(){ _this.fnDown() };}Drag.prototype.fnDown=function (ev) { var ev = ev || event; var _this=this; this.disX = ev.clientX - this.oDiv.offsetLeft; this.disY = ev.clientY - this.oDiv.offsetTop; document.onmousemove = function(){ _this.fnMove(); }; document.onmouseup =function(){ _this.fnUp(); };}Drag.prototype.fnMove=function(ev) { var ev = ev || event; this.oDiv.style.left = ev.clientX - this.disX + 'px'; this.oDiv.style.top = ev.clientY - this.disY + 'px';}Drag.prototype.fnUp=function () { document.onmousemove = null; document.onmouseup = null}</script></head><body> <div id="div1"></div> <div id="div2"></div></body></html><!DOCTYPE HTML><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>面向對象的繼承-2</title><style>#div1 {width: 100px; height: 100px; background: red; position: absolute;}#div2 {width: 100px; height: 100px; background: red; position: absolute;top:120px;}</style><script>window.onload=function(){ new Drag('div1'); new Drag('div2');}function Drag(id) { var _this=this; this.disX=0; this.disY=0; this.oDiv = document.getElementById(id); this.oDiv.onmousedown = function(){ _this.fnDown() };}Drag.prototype.fnDown=function (ev) { var ev = ev || event; var _this=this; this.disX = ev.clientX - this.oDiv.offsetLeft; this.disY = ev.clientY - this.oDiv.offsetTop; document.onmousemove = function(){ _this.fnMove(); }; document.onmouseup =function(){ _this.fnUp(); };}Drag.prototype.fnMove=function(ev) { var ev = ev || event; this.oDiv.style.left = ev.clientX - this.disX + 'px'; this.oDiv.style.top = ev.clientY - this.disY + 'px';}Drag.prototype.fnUp=function () { document.onmousemove = null; document.onmouseup = null}</script></head><body> <div id="div1"></div> <div id="div2"></div></body></html>
希望本文所述對大家JavaScript程序設計有所幫助。
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