JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="test" width="620px" height="200" class="wraper"></canvas>

JavaScript

function GaussProjInvCal(X, Y)  
	{  
	 var ProjNo;
	 var ZoneWide; ////带宽 
	 var output = []
	 var longitude1,latitude1, longitude0,latitude0, X0,Y0, xval,yval;  
	 var e1,e2,f,a, ee, NN, T,C, M, D,R,u,fai, iPI,sqrt,sin;  
	 iPI = 0.0174532925199433; ////3.1415926535898/180.0;   
	 a = 6378137.0;
	 f = 1.0 / 298.26; // CGC2000坐标系参数  
	 //ZoneWide = 6; ////6度带宽
	 ZoneWide = 3 ; ////3度带宽
	 
	 ProjNo = parseInt(X/1000000) ; //查找带号  
	 longitude0=(ProjNo-1)*ZoneWide + ZoneWide/2  
	 longitude0=longitude0*iPI ; //中央经线  
	 X0 = ProjNo*1000000+500000;   
	 Y0=0 
	 xval = X-X0; yval = Y-Y0; //带内大地坐标  
	 e2 = 2*f-f*f;  
	 e1 = (1.0-Math.sqrt(1-e2))/(1.0+Math.sqrt(1-e2));  
	 ee = e2/(1-e2);  
	 M = yval;  
	 u = M/(a*(1-e2/4-3*e2*e2/64-5*e2*e2*e2/256));  
	 fai = u+(3*e1/2-27*e1*e1*e1/32)*Math.sin(2*u)+(21*e1*e1/16-55*e1*e1*e1*e1/32)*Math.sin(4*u)+(151*e1*e1*e1/96)*Math.sin(6*u)+(1097*e1*e1*e1*e1/512)*Math.sin(8*u);  
	 C = ee*Math.cos(fai)*Math.cos(fai);  
	 T = Math.tan(fai)*Math.tan(fai);  
	 NN = a/Math.sqrt(1.0-e2*Math.sin(fai)*Math.sin(fai)); //字串1   
	  R = a*(1-e2)/Math.sqrt((1-e2*Math.sin(fai)*Math.sin(fai))*(1-e2*Math.sin(fai)*Math.sin(fai))*(1-e2*Math.sin  
	  (fai)*Math.sin(fai)));  
	 D = xval/NN;  
	 //计算经度(Longitude) 纬度(Latitude)  
	 longitude1 = longitude0+(D-(1+2*T+C)*D*D*D/6+(5-2*C+28*T-3*C*C+8*ee+24*T*T)*D*D*D*D*D/120)/Math.cos(fai);  
	 latitude1 = fai -(NN*Math.tan(fai)/R)*(D*D/2-(5+3*T+10*C-4*C*C-9*ee)*D*D*D*D/24+(61+90*T+298*C+45*T*T-256*ee-3*C*C)*D*D*D*D*D*D/720);   
	 //转换为度 DD  
	output.push(longitude1 / iPI)  
	output.push(latitude1 / iPI)
	 return output
	}