[英]Add new <option> to all dropdown <select> tags using javascript
我试图在默认选择的页面上添加一个下拉菜单选项“请选择”到每个下拉列表的顶部,使用类似这样的东西:
window.onload = function() {
$('select option[value="PSC"]').attr("selected",true);
};
这就是我用于下拉列表的内容:
window.onload = function AddItem(text,value) {
// Create an Option object
var opt = document.createElement("option");
// Add an Option object to Drop Down/List Box
document.getElementsByTagName("option").options.add(opt);
// Assign text and value to Option object
opt.text = 'Please select...';
opt.value = 'Please Select';
}
我是javascript的新手,有人可以指出我正确的方向来编译这一点,以便当页面加载每个下拉列表时获得一个名为“请选择”的默认选择选项
提前致谢
$(document).ready(function() {
$('<option>', {
text : 'Please select...',
value : 'Please select...',
selected : true
}).prependTo('select');
});
要么:
var select = document.getElementsByTagName("select"),
opt = '';
for (var i = 0; i < select.length; i++) {
opt = document.createElement("option");
// opt.selected = true;
opt.text = 'Please select...';
opt.value = 'Please Select';
select[i].options.add(opt);
}
修改了你的纯javascript函数到这个函数(这不影响已经选择的选项) DEMO jsfiddle
window.onload = function AddItem(text, value) {
// Get all Drop Down/List Box in document
var sel = document.getElementsByTagName("select");
for (var x = 0; x < sel.length; x++) {
// Create an Option object and set it's value/text
var opt = document.createElement("option");
opt.text = 'Please select...';
opt.value = 'Please Select';
//prepend in select box
sel[x].insertBefore(opt, sel[x].options[0])
}
}
干得好:
$('select').prepend('<option>Please select...</option>');
$(document).ready(function() {
$("select").prepend("<option value='' selected='selected'>Please select</option>");
});
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