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本文執行個體為大家分享了製作javascript簡易畫板的方法，供大家參考，具體內容如下
html：
<body id="bodys"><span id="eraser">清除所有</span><span id="colorbtn">筆畫顏色</span><input type="range" name="ram" id="ram" min="1" max="20" step="1" value="10"/><label id="ramnum">字型大小:10px</label><ul id="colorpanel"><li>黑色</li><li>紅色</li><li>綠色</li><li>藍色</li></ul></body>
CSS：
*{margin: 0;padding: 0; }.box_black{background-color: black;position: absolute;}.box_red{background-color: red;position: absolute;}.box_green{background-color: green;position: absolute;}.box_blue{background-color: blue;position: absolute;}#eraser{width: 80px;height: 50px;background-color: brown;display: inline-block;text-align: center;line-height: 50px;cursor: pointer;}#colorbtn{width: 80px;height: 50px;background-color: tomato;display: inline-block;text-align: center;line-height: 50px;cursor: pointer;}#colorpanel{width: 80px;height: 200px;list-style: none;margin-left: 88px;display: none;}#colorpanel>li{width: 80px;height: 50px;text-align: center;line-height: 50px;background-color: aquamarine;display: inline-block;cursor: pointer;}#colorpanel>li:hover{background-color: orange;}
javascript：
window.onload=function(){ //把類名存成一個數組 var classname=["box_black","box_red","box_green","box_blue"]; //預設類名為box_black var clsname=classname[0]; var oBody=document.getElementById("bodys"); var oDiv=oBody.getElementsByTagName("div"); var eraser=document.getElementById("eraser"); var colorbtn=document.getElementById("colorbtn"); var colorpanel=document.getElementById("colorpanel"); var ram=document.getElementById("ram"); var ramnum=document.getElementById("ramnum"); colorbtn.onmouseover=function(){ colorpanel.style.display="block"; } colorbtn.onmouseout=function(){ colorpanel.style.display="none"; } colorpanel.onmouseover=function(){ this.style.display="block"; } colorpanel.onmouseout=function(){ this.style.display="none"; } for(var i=0;i<colorpanel.children.length;i++){ colorpanel.children[i].index=i; colorpanel.children[i].onclick=function(){ //滑鼠點擊li切換類名來改變樣式 clsname=classname[this.index]; colorpanel.style.display="none"; } } //定義預設字型大小為10px var WIDTH="10px"; var HEIGHT="10px"; //通過滑動range來改變字型大小 ram.onmousemove=function(){ WIDTH=HEIGHT=ram.value+"px"; ramnum.innerHTML="字型大小:"+WIDTH; } //滑鼠點擊螢幕，通過滑動滑鼠不停建立div屬性節點，並且給它設定樣式document.onmousedown=function(){ document.onmousemove=function(event){ var oevent=event||window.event; var scrolltop=document.documentElement.scrollTop||document.body.scrollTop; var scrollleft=document.documentElement.scrollLeft||document.body.scrollLeft; var box=document.createElement("div"); box.className=clsname; box.style.width=WIDTH; box.style.height=HEIGHT; oBody.appendChild(box); box.style.left=scrollleft+oevent.clientX+"px"; box.style.top=scrolltop+oevent.clientY+"px";}}//當滑鼠按鍵鬆開，登出滑鼠滑動事件document.onmouseup=function(){document.onmousemove=null;}//當橡皮差按鈕被點擊，遍曆所有div並且把它們一一從父節點裡面移除eraser.onclick=function(){var oDiv=oBody.getElementsByTagName("div");for(var i=0;i<oDiv.length;i++){oBody.removeChild(oDiv[i]);}}//以下為取消按鈕的冒泡事件，因為我們點擊按鈕是不能繪製div的eraser.onmousedown=function(event){var ievent=event||window.event;ievent.cancelBubble=true;}colorbtn.onmousedown=function(event){var ievent=event||window.event;ievent.cancelBubble=true;}colorpanel.onmousedown=function(event){var ievent=event||window.event;ievent.cancelBubble=true;}ram.onmousedown=function(event){var ievent=event||window.event;ievent.cancelBubble=true;}}}
這是基於javascript的事件基礎寫的，比較簡易，其實還可以進一步進行最佳化。下面來看效果圖。
以上就是本文的全部內容，希望對大家的學習有所協助，也希望大家多多支援雲棲社區。
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