聚焦输入框加载

问题描述

如何在页面加载时将光标对准特定的输入框？

是否可以保留初始的文本值，并将光标置于输入的末尾？

 < input type =textsize =25id =myinputboxclass =input-text name =input2value =initial text/> 
  

解决方案

您的问题有两个部分。 >

1）如何在页面加载上集中输入？

您可以添加 autofocus 属性到输入。

 < input id =myinputboxtype =textautofocus> 
  

但是，所有浏览器可能不支持此功能，因此我们可以使用javascript。

  window.onload = function（）{
 var input = document.getElementById（myinputbox）。 
} 
  

2）如何将光标放在输入文本的末尾？

这是一个非jQuery解决方案，一些借用的代码来自。

  function placeCursorAtEnd（）{
 if（this.setSelectionRange）{
 //双倍的长度， Opera对于
 //是否不一致，回车是否为一个字符或两个。 
 var len = this.value.length * 2; 
 this.setSelectionRange（len，len）; 
} else {
 //这可能适用于没有setSelectionRange支持的浏览器。 
 this.value = this.value; 
} 
 
 if（this.nodeName ===TEXTAREA）{
 //如果需要，这将滚动一个textarea到底部
 this.scrollTop = 999999; 
} 
}; 
 
 window.onload = function（）{
 var input = document.getElementById（myinputbox）; 
 
 if（obj.addEventListener）{
 obj.addEventListener（focus，placeCursorAtEnd，false）; 
} else if（obj.attachEvent）{
 obj.attachEvent（'onfocus'，placeCursorAtEnd）; 
} 
 
 input.focus（）; 
} 
  

这里有一个我将如何用jQuery完成这个的例子。

 < input type =textautofocus> 
 
< script> 
 $（function（）{
 $（[autofocus]）。on（focus，function（）{
 if（this.setSelectionRange）{
 var len = this.value.length * 2; 
 this.setSelectionRange（len，len）; 
} else {
 this.value = this.value; 
} 
 this.scrollTop = 999999; 
}）。focus（）; 
}）; 
< / script> 
  

How can the cursor be focus on a specific input box on page load?

Is it posible to retain initial text value as well and place cursor at end of input?

<input type="text"  size="25" id="myinputbox" class="input-text" name="input2" value = "initial text" />

解决方案

There are two parts to your question.

1) How to focus an input on page load?

You can just add the autofocus attribute to the input.

<input id="myinputbox" type="text" autofocus>

However, this might not be supported in all browsers, so we can use javascript.

window.onload = function() {
  var input = document.getElementById("myinputbox").focus();
}

2) How to place cursor at the end of the input text?

Here's a non-jQuery solution with some borrowed code from another SO answer.

function placeCursorAtEnd() {
  if (this.setSelectionRange) {
    // Double the length because Opera is inconsistent about
    // whether a carriage return is one character or two.
    var len = this.value.length * 2;
    this.setSelectionRange(len, len);
  } else {
    // This might work for browsers without setSelectionRange support.
    this.value = this.value;
  }

  if (this.nodeName === "TEXTAREA") {
    // This will scroll a textarea to the bottom if needed
    this.scrollTop = 999999;
  }
};

window.onload = function() {
  var input = document.getElementById("myinputbox");

  if (obj.addEventListener) {
    obj.addEventListener("focus", placeCursorAtEnd, false);
  } else if (obj.attachEvent) {
    obj.attachEvent('onfocus', placeCursorAtEnd);
  }

  input.focus();
}

Here's an example of how I would accomplish this with jQuery.

<input type="text" autofocus>

<script>
$(function() {
  $("[autofocus]").on("focus", function() {
    if (this.setSelectionRange) {
      var len = this.value.length * 2;
      this.setSelectionRange(len, len);
    } else {
      this.value = this.value;
    }
    this.scrollTop = 999999;
  }).focus();
});
</script>

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