js 动态追加html 点击事件找不到方法，无法生效

在方法里绑定方法即可

function add_msg(that,number){
	var thislength = $(that).parent().parent().children().children(".template-msg").length;
	var str = '<div id="msg-'+thislength+'" class="template-msg">\n' +
			'\t\t\t\t\t<div class="form-group">\n' +
			'\t\t\t\t\t\t<label for="" class="control-label col-sm-2">模版消息key-'+thislength+'</label>\n' +
			'\t\t\t\t\t\t<div class="form-controls col-sm-8">\n' +
			'\t\t\t\t\t\t\t<input type="text" id="msg_key" class="form-control" name="template['+number+'][key]['+thislength+']" value="" />\n' +
			'\t\t\t\t\t\t</div>\n' +
			'\t\t\t\t\t</div>\n' +
			'\t\t\t\t\t<div class="form-group">\n' +
			'\t\t\t\t\t\t<label for="" class="control-label col-sm-2">模版消息value-'+thislength+'</label>\n' +
			'\t\t\t\t\t\t<div class="form-controls col-sm-8">\n' +
			'\t\t\t\t\t\t\t<input type="text" id="msg_text" class="form-control" name="template['+number+'][value]['+thislength+']" value="" />\n' +
			'\t\t\t\t\t\t</div>\n' +
			'\t\t\t\t\t</div>\n' +
			'\t\t\t\t\t<div class="form-group">' +
			'<input type="button" id="del_msg" style="float:right" value="删除模版消息-'+thislength+'" class="del_msg btn btn-primary btn-submit"/></div>\n' +
			'\t\t\t\t</div>';

	$(that).parent().prev(".msg-div").append(str);
// 绑定方法
	$(".del_msg").on('click',function() {
		console.log('msg-'+thislength);
		console.log($(this).parent().parent().remove());
		// $('#msg-'+thislength).remove()

	})
}