例如,我想要我的< textarea>宽度为4个空格：

textarea {
    -moz-tab-size: 4;
    -o-tab-size: 4;
    /* How would I do this in Chrome,Safari,and IE? */
}

[更新：]

我创建了一个tab大小的polyfill(Demo)：

<script> // tab-size polyfill
var codeElements = document.getElementsByTagName('code'),// Applies to all code elements. Adjust to your needs.
codeElementCount = codeElements.length,e = d.createElement('i');

if(e.style.tabSize !== '' && e.style.mozTabSize !== '' && e.style.oTabSize !== '') {
    for(var i = 0; i < codeElementCount; i++) {
        codeElements[i].innerHTML = codeElements[i].innerHTML.replace(/\t/g,'<span class="tab">&#9;</span>');
    }
}
</script>

<style>
.tab {
    width: 2.5em; /* adjust to your needs */
    display: inline-block;
    overflow: hidden;
}
</style>

注意：这不适用于< textarea> s,但仅适用于可以包含其他元素的元素.如果浏览器支持tab-size,它会改为使用它.