JS retains one digit and removes non-digits

This time I will bring you JS to retain one digit and then remove non-digits, and JS to retain one digit and then remove non-digits. What are the precautions?. Here is a practical case. Let’s take a look. one time.

//去除非数字
  var clearNoNum = function (item) {
    if (item!=null && item!=undefined) {
      //先把非数字的都替换掉，除了数字和.
      item = item.replace(/[^\d.]/g, "");
      //必须保证第一个为数字而不是.
      item = item.replace(/^\./g, "");
      //保证只有出现一个.而没有多个.
      item = item.replace(/\.{2,}/g, "");
      //保证.只出现一次，而不能出现两次以上
      item = item.replace(".", "$#$").replace(/\./g, "").replace("$#$", ".");
      //最多保留小数点后一位
      var arr = item.split(".");
      if (arr.length > 1) item = arr[0] + '.' + (arr[1].length > 1 ? arr[1].substr(0, 1) : arr[1]);
     }
    return item;
  }

Supplement:

Let’s take a look at js processing numbers to retain 2 decimal places. It is not enough to force 2 decimal places. Add .00

1, keep two decimal places //Function: round the floating point number, take 2 digits after the decimal point

2, //keep 2 digits For decimals, such as: 2, 00 will be added after 2. That is 2.00

nbsp;html> 
 
 
<meta> 
<title>Test</title> 
<script></script> 
 
<script>  
  //保留两位小数   
  //功能：将浮点数四舍五入，取小数点后2位  
  function toDecimal(x) {  
    var f = parseFloat(x);  
    if (isNaN(f)) {  
      return;  
    }  
    f = Math.round(x*100)/100;  
    return f;  
  }  
  //制保留2位小数，如：2，会在2后面补上00.即2.00  
  function toDecimal2(x) {  
    var f = parseFloat(x);  
    if (isNaN(f)) {  
      return false;  
    }  
    var f = Math.round(x*100)/100;  
    var s = f.toString();  
    var rs = s.indexOf(&#39;.&#39;);  
    if (rs < 0) {  
      rs = s.length;  
      s += &#39;.&#39;;  
    }  
    while (s.length <= rs + 2) {  
      s += &#39;0&#39;;  
    }  
    return s;  
  }  
  function fomatFloat(src,pos){    
     return Math.round(src*Math.pow(10, pos))/Math.pow(10, pos);    
  }  
  document.write("四舍五入 <br/>") 
  document.write("3.14159267保留2位小数：" + toDecimal(3.14159267)+"<br/>");  
  document.write("3.14159267强制保留2位小数：" + toDecimal2(3.14159267)+"<br/>");  
  document.write("3.14159267保留2位小数：" + toDecimal(3.14559267)+"<br/>");  
  document.write("3.14159267强制保留2位小数：" + toDecimal2(3.15159267)+"<br/>");  
  document.write("3.14159267保留2位小数：" + fomatFloat(3.14559267, 2)+"<br/>");  
  document.write("3.14159267保留1位小数：" + fomatFloat(3.15159267, 1)+"<br/>");  
  document.write("五舍六入 <br/>") 
  document.write("1000.003保留2位小数：" + 1000.003.toFixed(2)+"<br/>");  
  document.write("1000.08保留1位小数：" + 1000.08.toFixed(1)+"<br/>");  
  document.write("1000.04保留1位小数：" + 1000.04.toFixed(1)+"<br/>");  
  document.write("1000.05保留1位小数：" + 1000.05.toFixed(1)+"<br/>");  
  document.write("科学计数 <br/>") 
  document.write(3.1415+"科学技术后："+3.1415.toExponential(2)+"<br/>");  
  document.write(3.1455+"科学技术后："+3.1455.toExponential(2)+"<br/>");  
  document.write(3.1445+"科学技术后："+3.1445.toExponential(2)+"<br/>");  
  document.write(3.1465+"科学技术后："+3.1465.toExponential(2)+"<br/>");  
  document.write(3.1665+"科学技术后："+3.1665.toExponential(1)+"<br/>");  
  document.write("精确到n位，不含n位 <br/>") 
  document.write("3.1415精确到小数点第2位" + 3.1415.toPrecision(2)+"<br/>");  
  document.write("3.1455精确到小数点第3位" + 3.1465.toPrecision(3)+"<br/>");  
  document.write("3.1445精确到小数点第2位" + 3.1415.toPrecision(2)+"<br/>");  
  document.write("3.1465精确到小数点第2位" + 3.1455.toPrecision(2)+"<br/>");  
  document.write("3.166592679287精确到小数点第5位" + 3.141592679287.toPrecision(5)+"<br/>");  
</script>  
 
<input> 
 

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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