系统开发时很多地方需要有焦点效果，例如：鼠标点击聚焦，地图定位，在图片上突出显示，焦点定位页面元素。
本小功能通过jquery和graphics二次开发，实现通过鼠标点击页面任何区域，聚焦当前点击位置。适用于页面任何元素的位置效果。
首先引入jquery引擎包:jquery-1.4.2.min.js和graphics.js
源码下载地址
编写实现效果js文件，qfocus.js,源码如下：
代码如下:
var qfocus = {
config:{
"bar_dis":true,//横竖条显示或隐藏
"circle_dis":true,//焦点隐藏
"bar_color":"black",//线条颜色
"circle_color":"red",//圆圈颜色
"rect_color":"green"//方块颜色
},
locationTimer: null,//时间控制标识符
onmouseClick: function(ev){//鼠标点击获取鼠标位置画聚焦效果
var point = this.mousePosition(ev);
this.showFocus(point);
},
onclickElement:function(obj) {//鼠标点击获取坐标做焦点
var _point = this.elementPosition(obj);
this.showFocus(_point);
},
showFocus:function (point) {//显示焦点效果
if (this.locationTimer) {
clearTimeout(this.locationTimer);
} //清除定时器
var mapDiv = "#mapdiv";
var _point = point;
var canvas = $("#canvas");
var vLine = $("#vline");
var hLine = $("#hline");
//焦点隐藏或显示
if (this.config["circle_dis"] == true) {
if (!$("#canvas").attr("id")) {
canvas = '';
$(canvas).appendTo("body");
} else {
canvas.css("left", (_point.x - 25) + "px");
canvas.css("top", (_point.y - 25) + "px");
canvas.show();
}
paper = Raphael("canvas");
paper.clear();
var rect = paper.rect(20, 20, 10, 10, 0);
rect.attr("stroke", this.config["rect_color"]);
rect.attr("stroke-width", 1);
}
//是否显示横竖条
if (this.config["bar_dis"] == true) {
if (!$("#vline").attr("id")) {
vLine = "";
$(vLine).appendTo("body");
} else {
$(vLine).css("left",(_point.x) + "px");
vLine.show();
}
if (!$("#hline").attr("id")) {
var hLine = "";
$(hLine).appendTo("body");
} else {
$("#hline").css("top",(_point.y ) + "px");
hLine.show();
}
}
this.hideFocus();
return true;
}, hideFocus:function() {//隐藏焦点效果
if (paper != null) {
var circle = paper.circle(25, 25, 30);
circle.attr("stroke", this.config["circle_color"]);
circle.attr("stroke-width", 1);
var anim = Raphael.animation({
r: 5
}, 900, null, function(){
this.locationTimer = setTimeout(function(){
$("#canvas").hide(); //焦点
$("#vline").hide(); //横条
$("#hline").hide(); //竖条
clearTimeout(this.locationTimer);
}, 500);
});
circle.animate(anim);
} else {
this.locationTimer = setTimeout(function(){
$("#canvas").hide(); //焦点
$("#vline").hide(); //横条
$("#hline").hide(); //竖条
clearTimeout(this.locationTimer);
}, 500);
}

},mousePosition:function (e) {
var x,y;
var e = e||window.event;
return {
x:e.clientX+document.body.scrollLeft+document.documentElement.scrollLeft,
y:e.clientY+document.body.scrollTop+document.documentElement.scrollTop
}
},elementPosition:function( oElement ) {
var x2 = 0;
var y2 = 0;
var width = oElement.offsetWidth;
var height = oElement.offsetHeight;
var postion = "";
if( typeof( oElement.offsetParent ) != 'undefined' ){
for( var posX = 0, posY = 0; oElement; oElement = oElement.offsetParent ) {
posX += oElement.offsetLeft;
posY += oElement.offsetTop;
}
x2 = posX + width;
y2 = posY + height;
postion = [ posX, posY ,x2, y2];
} else{
x2 = oElement.x + width;
y2 = oElement.y + height;
postion = [ oElement.x, oElement.y, x2, y2];
}
var x = postion[0] + ((postion[2] - postion[0])/2);
var y = postion[1] + ((postion[3] - postion[1])/2);
return {"x":x,"y":y};
}
}

html页面调用源码：
代码如下:









function forward(ev){
qfocus.onmouseClick(ev);
}
document.onmousedown=forward;

效果图片：

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