[转]巧用sel.options[sel.selectedIndex].text与try{}catch{e}{}操作SELECT选项值
当select.value=value被赋予一个不存在的值时如果在这个时候用sel.options.text来获取当前选择文本会抛出异常。本文主要思想就是catch抛出的异常来断定select中不存在此value的选项，感觉这样做比循环获取每个option的value与新的value值比对是否相等更有效率，废话不多说，上菜！<html><head><title>JS</title><script type="text/javascript">function $(id) { return document.getElementById(id); } String.prototype.trim=function() { return this.replace(/(^\s*)|(\s*$)/g,""); } function init() { var originalSel = $("originalSel"); originalSel.options=new Option("text1","1"); originalSel.options=new Option("text2","2"); originalSel.options=new Option("text3","3"); originalSel.options=new Option("text4","4"); originalSel.options=new Option("text5","5"); } function alertText(){ var value = prompt('请您输入value值',''); if(value==null||value.trim()=="") { return; } var originalSel = $("originalSel"); originalSel.value=value; try{ var text = originalSel.options.text; alert("value="+value+"对应的text是"+text); }catch(e){ if(originalSel.options) { originalSel.options.selected=true; } alert("您输入的value不存在！"); } } function add() { var textValue = prompt("请你输入Text,Value","text,value"); if(textValue==null) { alert("请您输入text,value!"); return; } var ary = textValue.split(","); if(ary.length<2||ary.trim()==""||ary.trim()=="") { alert("key,value值不能为空！"); return; } var text = ary; var value = ary; var selObj = $("originalSel"); selObj.value=value; try{ selObj.options.text; alert("select中已存在value为"+value+"的选项！"); return; }catch(e){ selObj.options=new Option(text,value); selObj.value=value; alert("增加成功！"); } } function remove(){ var value = prompt('请您输入value值',''); if(value==null||value.trim()=="") { return; } var originalSel = $("originalSel"); originalSel.value=value; try{ originalSel.options.text; originalSel.remove(originalSel.selectedIndex); alert("删除成功！"); }catch(e){ if(originalSel.options) { originalSel.options.selected=true; } alert("select中不存在value="+value+"的选项！"); } } </script> </head><body ><select id="originalSel" style="width:150px"></select><br><input type="button"value="alertText"><input type="button"value="addOption"><input type="button"value="removeOption"></body></html>
原帖地址：http://ilovejsj.iteye.com/blog/466259
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