不可以 ，无法为默认占位符着色，但是您可以创建类似于占位符的元素。因此，您可以为字母着色。这是默认占位符的解决方法。

请注意，我正在使用opacity: 0.5，您可以根据需要进行更改。

HTML

.input-field {

    position: relative;

    display: inline-block;

}

.input-field > label {

    position: absolute;

    left: 0.5em;

    top: 50%;

    margin-top: -0.5em;

    opacity: 0.5;

}

.input-field > input[type=text]:focus + label {

    display: none;

}

.input-field > label > span {

    letter-spacing: -2px;

}

.first-letter {

    color: red;

}

.second-letter {

    color: blue;

}

.third-letter {

    color: orange;

}

.fourth-letter {

    color: green;

}

.fifth-letter {

    color: yellow;

}


    <div class="input-field">

        <input id="input-text-field" type="text"></input>

        <label for="input-text-field">

            <span class="first-letter">H</span>

            <span class="second-letter">E</span>

            <span class="third-letter">L</span>

            <span class="fourth-letter">L</span>

            <span class="fifth-letter">O</span>

        </label>

    </div>

工作小提琴

更新：

仅CSS（ 含:placeholder-shown）

上面的小提琴有一个Bug ，当您在文本框中键入内容并单击外部时，占位符将再次出现在输入的文本上方。

因此，要使其完美，我们可以使用:placeholder-shown除chrome和firefox之外没有太多支持的工具。

这是代码：

.input-field {

  position: relative;

  display: inline-block;

}



.input-field > label {

  position: absolute;

  left: 0.5em;

  top: 50%;

  margin-top: -0.5em;

  opacity: 0.5;

  display: none;

}



.input-field > input[type=text]:placeholder-shown + label {

  display: block;

}



.input-field > label > span {

  letter-spacing: -2px;

}



.first-letter {

  color: red;

}



.second-letter {

  color: blue;

}



.third-letter {

  color: orange;

}



.fourth-letter {

  color: green;

}



.fifth-letter {

  color: yellow;

}


<div class="input-field">

  <input id="input-text-field" type="text" placeholder=" "></input>

  <label for="input-text-field">

    <span class="first-letter">H</span>

    <span class="second-letter">E</span>

    <span class="third-letter">L</span>

    <span class="fourth-letter">L</span>

    <span class="fifth-letter">O</span>

  </label>

</div>

使用JS（ 不带:placeholder-shown）：

addListenerMulti(document.getElementById('input-text-field'), 'focus keyup', blurme);



function blurme(e) {

  var element = e.currentTarget;

  element.classList[(element.value.length !== 0) ? "add" : "remove"]('hide-placeholder');

}



function addListenerMulti(el, s, fn) {

  s.split(" ").forEach(function(e) {

    return el.addEventListener(e, fn, false)

  });

}


.input-field {

  position: relative;

  display: inline-block;

}

.input-field > label {

  position: absolute;

  left: 0.5em;

  top: 50%;

  margin-top: -0.5em;

  opacity: 0.5;

}

.hide-placeholder + label {

  display: none;

}

.input-field > label > span {

  letter-spacing: -2px;

}

.first-letter {

  color: red;

}

.second-letter {

  color: blue;

}

.third-letter {

  color: orange;

}

.fourth-letter {

  color: green;

}

.fifth-letter {

  color: yellow;

}


<div class="input-field">

  <input id="input-text-field" type="text"></input>

  <label for="input-text-field">

    <span class="first-letter">H</span>

    <span class="second-letter">E</span>

    <span class="third-letter">L</span>

    <span class="fourth-letter">L</span>

    <span class="fifth-letter">O</span>

  </label>

</div>