js method to draw a line between two points_javascript skills-JS Tutorial-php.cn

js method to draw a line between two points_javascript skills

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Release： 2016-05-16 15:59:43

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The example in this article describes the method of drawing a line between two points in js. Share it with everyone for your reference. The specific analysis is as follows:

I’ve been a little bored lately. I’ve been thinking about it for a long time and came up with an idea to kill time, which is to make a js version of Lianliankan.

Drawing a line between two points is only part of the most basic function of Lianliankan, so the line I drew is only a polyline, and it can only fold to the left. Later, the direction of the polyline will be determined based on the position of the picture in Lianliankan. .

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>两点之间画折线</title>
<style type="text/css">
body{
 font-size:12px;
}
</style>
</head>
<script type="text/javascript">
<!--
var dot=new Array();
document.onmousedown =function(a) 
{ 
 //若div存在，则删除
 if(document.getElementById('line_div')){
 var clearDiv=document.getElementById("line_div");
 clearDiv.parentNode.removeChild(clearDiv);
 }
 //按下时创建一个事件
 if(!a) a=window.event;
 //获取x轴、y轴坐标
 var x=a.clientX;
 var y=a.clientY;
 //当数组长度大于等于4时，清空数组
 if(dot.length>=4) dot.splice(0,4);
 //将x、y添加到数组中,数组中保存了两组坐标值，相当于页面上的A(x1,y1)、B(x2,y2)两点
 dot.push(x,y);
 //当数组长度为4时，画线。
 if(dot.length==4){
 //计算div的长和宽
 var width=Math.abs(dot[0]-dot[2]);
 var height=Math.abs(dot[1]-dot[3]);
 //在页面上定位div左上角的具体位置
 var left=dot[0]-dot[2]<0&#63;dot[0]:dot[2];
 var top=dot[1]-dot[3]<0&#63;dot[1]:dot[3];
 //创建div
 var div=document.createElement("div");
 div.innerHTML=' <div id="line_div" style="width:'+width+'px;height:'+height+'px;position:absolute;visibility:visible;left:'+left+'px;top:'+top+'px;border-left:1px solid #cdcdcd;border-top:1px solid #cdcdcd;"></div>';
 document.body.appendChild(div);
 }
} 
-->
</script>
<body>
</body>
</html>

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I hope this article will be helpful to everyone’s JavaScript programming design.