javascript IE 11 无法获取未定义或空引用的属性“长度”
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IE 11 Unable to get property 'length' of undefined or null reference
提问by brodster
I am getting an error in internet explorer 11
我在 Internet Explorer 11 中遇到错误
"Unable to get property 'length' of undefined or null reference" on line
在线“无法获取未定义或空引用的属性‘长度’”
if (window.localStorage.length !== 0)
it works fine on chrome and Firefox, not sure whats causing it
它在 chrome 和 Firefox 上运行良好，不确定是什么原因造成的
<script>
function initialize() {
// test to see if brouser supports storeage api
var bSupportsLocal = (('localStorage' in window) && window.localStorage !== null );
if (!bSupportsLocal) {
document.getElementById('infoform').innerHTML = "<p> Sorry, This browser does not suport local storage. </p>";
return;
}
if (window.localStorage.length !== 0) {
document.getElementById('firstName').value = window.localStorage.getItem('firstName');
$.mobile.navigate("#benefits-facts");
}
}
function storeLocalContent(fName) {
window.localStorage.setItem('firstName', fName);
}
function clearLocalContent(strToStore) {
window.localStorage.clear();
}
window.onload = initialize;
</script>
回答by Anil Talla
I thought in IE window.localStorageis undefined initially. You are checking is localStoragein the windowand its not null. So bSupportLocalis setting to true. Its executing window.localStorage.lengthstatement. Undefined.length causing error.
Here is the code
我认为在 IEwindow.localStorage中最初是未定义的。您正在检查是localStorage在window和不是null。因此，bSupportLocal被设置为true。它的执行window.localStorage.length语句。Undefined.length 导致错误。这是代码
var bSupportsLocal = window['localStorage'] || '';
If localStorage is having some value it will assign to bSupportsLocal, otherwise it is assigned with empty string.
如果 localStorage 有某个值，它将分配给 bSupportsLocal，否则分配给空字符串。
