select2的使用及問題

　　這個插件是基於Select的擴展插件，可以提供更加豐富的功能和用戶體驗，它的github官網地址爲:https://select2.github.io/，具體的使用案例，能夠參考地址：https://select2.github.io/examples.html。

　　select2是對select進行美化，網上也有不少列子。在項目開發中，遇到了使用select2進行下拉選擇，可是下拉選項仍是必填項，在網上找了好多解決辦法都不行，最後採起的追加，解決了！！　　　　

必填校驗：　

$("#nativePlace").select2();
$("#userId").select2();
$("#studyMajor").select2();
$("#nation").select2();
var str= "<div class='tip-yellowsimple' id='nativePlace_error' onclick=\"hide_error(this,'nativePlace')\" style='left: 655px; top: 148px;cursor: pointer;visibility: hidden;'>"+
"<div class='tip-inner tip-bg-image'>"+
"<label class='error'>不能爲空</label>"+
"</div>"+
"<div class='tip-arrow tip-arrow-left' style='visibility: inherit;position: absolute;overflow: hidden;font: 1px/1px sans-serif;'></div>"+
"</div>"+
"<div class='tip-yellowsimple' id='userId_error' onclick=\"hide_error(this,'userId')\" style='left: 352px; top: 96px;cursor: pointer;visibility: hidden;'>"+
"<div class='tip-inner tip-bg-image'>"+
"<label class='error'>不能爲空</label>"+
"</div>"+
"<div class='tip-arrow tip-arrow-left' style='visibility: inherit;position: absolute;overflow: hidden;font: 1px/1px sans-serif;'></div>"+
"</div>"+
"<div class='tip-yellowsimple' id='nation_error' onclick=\"hide_error(this,'nation')\" style='left: 948px; top: 96px;cursor: pointer;visibility: hidden;'>"+
"<div class='tip-inner tip-bg-image'>"+
"<label class='error'>不能爲空</label>"+
"</div>"+
"<div class='tip-arrow tip-arrow-left' style='visibility: inherit;position: absolute;overflow: hidden;font: 1px/1px sans-serif;'></div>"+
"</div>";
/* "<div class='tip-yellowsimple' id='studyMajor_error' onclick=\"hide_error(this,'studyMajor')\" style='left: 948px; top: 178px;cursor: pointer;'>"+
"<div class='tip-inner tip-bg-image'>"+
"<label class='error'>不能爲空</label>"+
"</div>"+
"<div class='tip-arrow tip-arrow-left' style='visibility: inherit;position: absolute;overflow: hidden;font: 1px/1px sans-serif;'></div>"+
"</div>"+ */
$("body").append(str);

$(window).resize(function(){
if($("#nativePlace_error").css("visibility") == "visible"){
check("nativePlace",658+($(document).width()-1183)/2+"px");
}
if($("#userId_error").css("visibility") == "visible"){
check("userId",360+($(document).width()-1183)/2+"px");
}
if($("#nation_error").css("visibility") == "visible"){
check("nation",960+($(document).width()-1183)/2+"px");
}
});

$("#nativePlace").on("select2-focus", function(e) { check("nativePlace",658+($(document).width()-1183)/2+"px");});
$("#userId").on("select2-focus", function(e) { check("userId",360+($(document).width()-1183)/2+"px");});
/* $("#studyMajor").on("select2-focus", function(e) { check("studyMajor","948px");}); */
$("#nation").on("select2-focus", function(e) { check("nation",960+($(document).width()-1183)/2+"px");});
})

清空：

$("#nation").val(null).trigger("change");