先看效果图：
要求：当输入框获得焦点时，自动显示验证图片。
代码如下（学习而已，仅供参考）：
复制代码 代码如下:
/***********************下是验证码对象*****************/
var validation = {};
validation.init = function(elename,imagesrc){
this.image = imagesrc;
$('#'+elename).focusin(function(){
validation.show(elename);
});
}
validation.image = '';
validation.display=false;
validation.width = '100px';
validation.height = '30px';
validation.div = null;
validation.show = function(elename){
if(this.display==false){
//首次显示
if(this.div==null){
$('#'+elename).after('
');
this.div = $('#div_validation_'+elename);
this.div.css('position','absolute');
this.div.css('cursor','pointer');
this.div.css('border','1px solid #ccc');
this.div.css('background-color','#fff');
this.div.css('background-position','center');
this.div.css('background-repeat','no-repeat');
this.div.css('height',this.height);
this.div.css('width',this.width);
var objoffset = $('#'+elename).offset();
objoffset.top+=$('#'+elename).height()+6;
this.div.offset(objoffset);
this.div.css('background-image','url('+validation.image+'&_t='+new date()+')');
this.div.css('display','inline-block');
this.display = true;
//点击更换
this.div.click(function(){
validation.div.css('background-image','url('+validation.image+'&_t='+new date()+')');
});
}
else{
this.div.css('background-image','url('+validation.image+'&_t='+new date()+')');
this.display = true;
this.div.css('display','inline-block');
}
}
}
validation.hide =function(){
if(this.display==true){
this.display = false;
this.div.hide();
}
}
使用方式：
复制代码 代码如下:
//验证码对象初始化
validation.init('validation','ajax.ashx?handle=validation');
// 输入框id 验证图片地址
//隐藏
validation.hide();