清空select的项
// document.all.objSelect.options.length = 0;
如果留下第一行的话就是
// document.all.objSelect.options.length = 1;
[color=red]判断select选项中 是否存在Value="paraValue"的Item[/color]
function jsSelectIsExitItem(objSelect,objItemValue){ var isExit = false; for(var i=0;i<objSelect.options.length;i++) { if(objSelect.options[i].value == objItemValue) { isExit = true; break; } } return isExit;}
[color=red]向select选项中 加入一个Item[/color]
function jsAddItemToSelect(objSelect,objItemText,objItemValue){ //判断是否存在 if(jsSelectIsExitItem(objSelect,objItemValue)) { alert("该Item的Value值已经存在"); } else { var varItem = new Option(objItemText,objItemValue);// objSelect.options[objSelect.options.length] = varItem; objSelect.options.add(varItem); alert("成功加入"); } }
[color=red]从select选项中 删除一个Item[/color]
function jsRemoveItemFromSelect(objSelect,objItemValue){ //判断是否存在 if(jsSelectIsExitItem(objSelect,objItemValue)) { for(var i=0;i<objSelect.options.length;i++) { if(objSelect.options[i].value == objItemValue) { objSelect.options.remove(i); break; } } alert("成功删除"); } else { alert("该select中 不存在该项"); } }
[color=red]修改select选项中 value="paraValue"的text为"paraText"[/color]
function jsUpdateItemToSelect(objSelect,objItemText,objItemValue){ //判断是否存在 if(jsSelectIsExitItem(objSelect,objItemValue)) { for(var i=0;i<objSelect.options.length;i++) { if(objSelect.options[i].value == objItemValue) { objSelect.options[i].text = objItemText; break; } } alert("成功修改"); } else { alert("该select中 不存在该项"); } }
[color=red]设置select中text="paraText"的第一个Item为选中[/color]
function jsSelectItemByValue(objSelect,objItemText){ //判断是否存在 var isExit = false; for(var i=0;i<objSelect.options.length;i++) { if(objSelect.options[i].text == objItemText) { objSelect.options[i].selected = true; isExit = true; break; } } //Show出结果 if(isExit) { alert("成功选中"); } else { alert("该select中 不存在该项"); } }
[color=red]设置select中value="paraValue"的Item为选中[/color]
//document.all.objSelect.value = objItemValue;
[color=red]得到select的当前选中项的value[/color]
//var currSelectValue = document.all.objSelect.value;
[color=red]得到select的当前选中项的text[/color]
//var currSelectText = document.all.objSelect.options[document.all.objSelect.selectedIndex].text;
[color=red]得到select的当前选中项的Index[/color]
//var currSelectIndex = document.all.objSelect.selectedIndex;
完整例子
<!doctype html public "-//w3c//dtd html 4.0 transitional//en"><html><head><title>js控制select增删改,选中,清空, 判断控件是否存在</title><meta name="keywords" content="javascript select options text value add modify delete set"><meta name="description" content="javascript select options text value add modify delete set"><script language="javascript"><!--function watch_ini(){ // 初始for(var i=0; i<arguments.length; i++){ var oOption=new Option(arguments[i],arguments[i]); document.getElementById("MySelect")[i]=oOption;}}function watch_add(f){ // 增加 var oOption=new Option(f.word.value,f.word.value); f.keywords[f.keywords.length]=oOption;}function watch_sel(f){ // 编辑f.word.value = f.keywords[f.keywords.selectedIndex].text;}function watch_mod(f){ // 修改f.keywords[f.keywords.selectedIndex].text = f.word.value;}function watch_del(f){ // 删除f.keywords.remove(f.keywords.selectedIndex);}function watch_set(f){ // 保存var set = "";for(var i=0; i<f.keywords.length; i++){set += f.keywords[i].text + ";";}confirm(set);}//--></script></head><body><form name="watch" method="post" action=""><select id="MySelect" name="keywords" size="10" onchange="watch_sel(this.form)"></select><br><script language="javascript"><!--watch_ini("黑","色","头","发","紫","色","头","发"); // 初始关键词//--></script><input type="text" name="word" /><br /><input type="button" value="增加" onclick="watch_add(this.form);" /><input type="button" value="修改" onclick="watch_mod(this.form);" /><input type="button" value="删除" onclick="watch_del(this.form);" /><input type="button" value="保存" onclick="watch_set(this.form);" /></form></body></html>
黑色头发:http://heisetoufa.iteye.com/
