在页面加载时使用类而不是输入id上的js自动对焦

Question

我有一个网站，我想使用js在页面加载时将焦点设置为输入字段。我无法更改以下代码。这是输入标签：

input class="form-control ng-pristine ng-valid ng-scope ng-touched"
      ng-model="query.q" type="text"
      placeholder="Enter search terms - use quotes for phrases"
      kw-clearable-input=""

我在下面试过js看其他类似的主题，但没有运气：

function setFocusToTextBox(){
    document.getElementsByClassName("form-control ng-pristine ng-valid ng-scope ng-touched")[0]; element.focus();
}

任何帮助将非常感激。谢谢。

Answer 1

问题是焦点函数中没有定义元素。

正确定义时，它正在工作。

function setFocusToTextBox()
{ 
  let element = document
    .getElementsByClassName("form-control ng-pristine ng-valid ng-scope ng-touched")[0]; 
  
  element.focus();
}

setFocusToTextBox();

<input class="form-control ng-pristine ng-valid ng-scope ng-touched" ng-model="query.q" type="text" placeholder="Enter search terms - use quotes for phrases" kw-clearable-input=""/>

您还可以删除元素并使用焦点加入查询，如下所示：

function setFocusToTextBox()
{ 
  document.getElementsByClassName("form-control ng-pristine ng-valid ng-scope ng-touched")[0].focus();
}

setFocusToTextBox();

<input class="form-control ng-pristine ng-valid ng-scope ng-touched" ng-model="query.q" type="text" placeholder="Enter search terms - use quotes for phrases" kw-clearable-input=""/>

这里提供的布局：

function setFocusToTextBox()
{ 
  document.querySelector( '.input-group.dropdown input' ).focus();
}

setFocusToTextBox();

<div class="input-group dropdown" dropdown="" keyboard-nav="" is-open="opt.showFqDropdown"> <span style="position: relative;"> <input class="form-control ng-pristine ng-valid ng-scope ng-touched" ng-model="query.q" type="text" placeholder="Enter search terms - use quotes for phrases" kw-clearable-input=""/>
</span>
</div>

Answer 2

你可以使用autofocus

<input class="form-control ng-pristine ng-valid ng-scope ng-touched" ng- 
 model="query.q"
 type="text"
 placeholder="Enter search terms - use quotes for phrases"
 kw-clearable-input="" 
 autofocus>