本文实例讲述了JQuery+CSS实现图片上放置按钮的方法。分享给大家供大家参考。具体分析如下：
position:relative日常应用的时候一般是设置给position:absolute;的父层的,
父层position:relative; 子层position:absolute;的话, 就是依照父层的边界进行定位的,
不然position:absolute 会逐层向上寻找设置了position:relative的元素边界, 直到body元素..
第一种写法（连同CSS一起追加进去）
var freeOne="";
freeOne=$(".freePreviewOne").attr("data-url");
if(freeOne==null){
//没有免费视频
}else{
$("#coursePicture").append("<a class='hide-650 fade5' "+
"style='top:94px;left:150px;position:absolute;z-index:100; " +
" width: 180px;height: 60px;border: 2px solid white;" +
"display: block;color: white;text-decoration: none;" +
"letter-spacing: 1px;font-size: 16px;line-height: 20px;" +
"text-align:center;padding-top:18px;" +
"background-color: rgba(0, 0, 0, 0.44);" +
"-webkit-backface-visibility: hidden;-webkit-transition: all .3s ease-in-out;" +
"-moz-transition: all .3s ease-in-out;-ms-transition: all .3s ease-in-out;" +
"-o-transition: all .3s ease-in-out;" +
"border-radius: 10px;'"+
"href='#modal' data-toggle='modal' "+
"data-url='"+freeOne+"'> "+
"<span class='contactus' style='font-size:26px;'>试 看</span> <span class='glyphicon glyphicon-play' style='font-size:20px;top:0;bottom:2px;'></span> </a>"
);
}
页面：
<div class="es-row-wrap container-gap course-cover">
<div class="row row-5-7 course-cover-heading">
<div id="coursePicture" class="col-sm-5 picture hidden-xs" style="position: relative;">
<#if course.coverImage?has_content>
<img src="${course.coverImage}" class="img-responsive" width="436px" height="245px" />
<#else>
<img src="/resources/assets/img/default/course-large.png" class="img-responsive" />
</#if>
</div>
</div>
</div>
第二种写法：
//在课程图片上放置按钮
/* <a class="button hide-650 fade5" href="#modal" data-toggle="modal" data-url="/course/hyjgz2np/lesson/preview?lectureId=hyjgz2np0.49618492345325650.04212287697009742"> <span class="contactus"><strong>试看</strong></span> </a>
*/
//$("#coursePicture").append("<a class='btn btn-sm btn-info' href='#' style='top:120px;left:180px;position:absolute;z-index:100;'>试看</a>");
var freeOne="";
freeOne=$(".freePreviewOne").attr("data-url");
if(freeOne==null){
//没有免费视频
}else{
$("#coursePicture").append("<a class='freePreviewPicture hide-650 fade5' "+
"href='#modal' data-toggle='modal' "+
"data-url='"+freeOne+"'> "+
"<span class='contactus' style='font-size:26px;'>试 看</span> <span class='glyphicon glyphicon-play' style='font-size:20px;top:0;bottom:2px;'></span> </a>"
);
}
页面：
<style>
.freePreviewPicture{
top:94px;
left:150px;
position:absolute;
z-index:100;
width: 180px;
height: 60px;
border: 2px solid white;
display: block;
color: white;text-decoration: none;
letter-spacing: 1px;font-size: 16px;
line-height: 20px;
text-align:center;padding-top:18px;
background-color: rgba(0, 0, 0, 0.44);
-webkit-backface-visibility: hidden;
-webkit-transition: all .3s ease-in-out;
-moz-transition: all .3s ease-in-out;
-ms-transition: all .3s ease-in-out;
-o-transition: all .3s ease-in-out;
border-radius: 10px;
}
</style>
<div class="es-row-wrap container-gap course-cover">
<div class="row row-5-7 course-cover-heading">
<div id="coursePicture" class="col-sm-5 picture hidden-xs" style="position: relative;">
<#if course.coverImage?has_content>
<img src="${course.coverImage}" class="img-responsive" width="436px" height="245px" />
<#else>
<img src="/resources/assets/img/default/course-large.png" class="img-responsive" />
</#if>
</div>
</div>
</div>
运行效果图如下：
希望本文所述对大家的jQuery程序设计有所帮助。
