js code that limits the input value to floating point for the input box

The following editor will bring you a js code that limits the input value of the input box to floating point. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor and take a look.

In some projects, for example, the amount uses floating point type. For input restrictions, you can refer to the following

<script>
　　function only_num(obj){
　　　　//得到第一个字符是否为负号
　　　　var num = obj.value.charAt(0);
　　　　//先把非数字的都替换掉，除了数字和.
　　　　obj.value = obj.value.replace(/[^\d\.]/g,&#39;&#39;);
　　　　//必须保证第一个为数字而不是.
　　　　obj.value = obj.value.replace(/^\./g,&#39;&#39;);
　　　　//保证只有出现一个.而没有多个.
　　　　obj.value = obj.value.replace(/\.{2,}/g,&#39;.&#39;);
　　　　//保证.只出现一次，而不能出现两次以上
　　　　obj.value = obj.value.replace(&#39;.&#39;,&#39;$#$&#39;).replace(/\./g,&#39;&#39;).replace(&#39;$#$&#39;,&#39;.&#39;);
　　　　//如果第一位是负号，则允许添加
　　　　if(num == &#39;-&#39;){
　　　　　　obj.value = &#39;-&#39;+obj.value;
　　　　}
　　}
</script>

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