var qcanvas = new Qcanvas(
		{
			id:'qcanvas',
			width:500,
			height:500,  
			// mousedown:function(){
			// 	document.getElementById('contextMenu').style.display = 'none';
			// }
		}) 
 		
    qcanvas.qquadraticCurve.quadraticCurve({
		start:[20,20],
		handler:[100,200],
		end:[100,20],
		width:1,
		like:'<-->',
		color:'red',
		drag:true,
		withText:'我是个二次曲线'
	}) 


     qcanvas.qquadraticCurve.quadraticCurve({
		start:[200,100],
		handler:[230,150],
		end:[230,80],
		width:1,
		like:'->',
		color:'blue',
		drag:true,
		withText:'我也是个二次曲线'
	})