用javascript实现不按Ctrl实现Multiple Select多选

</p> <p><title> new document </title> </p> <p>宝马<br /> 保时捷<br /> 奔驰<br /> 桑塔纳<br /> 林肯<br /> 标志<br /> 大公共 </p> <p><!--<br /> string.prototype.trimend = function(trimstring) {<br /> var re = new regexp(trimstring+"*$", "g");<br /> return this.replace(re, "");<br /> };<br /> array.prototype.indexof = function(itemvalue) {<br /> var nindex = -1;<br /> for (var i=0; i<this.length; i++)<br /> {<br /> if (this[i] == itemvalue)<br /> nindex = i;<br /> }<br /> return nindex;<br /> };<br /> var ospan = document.getelementbyid("spaoutput");<br /> var osele = document.getelementbyid("o<a href="https://www.kunjuke.com/tag/2050/" title="select" target="_blank">select</a>");<br /> var obtn = document.getelementbyid("btnshowselected");<br /> obtn.onclick = function() {<br /> alert(getselectedindexes(osele));<br /> };<br /> function getselectedindexes(osele)<br /> {<br /> var sselectedindexes = "";<br /> var separator = ",";<br /> for (var i=0; i -1)<br /> {<br /> this.options[this.selectedindex].selected = false;<br /> this.selectedindexes.splice(j, 1);<br /> }<br /> if (this.selectedindexes.length > 0)<br /> {<br /> var nselectedindex;<br /> for (var i=0; i </p> <p>
[ctrl+a 全选 注:如需引入外部js需刷新才能执行]