form表单控制文本，数字输入位数和小数位数

html:
<input type="number" oninput="value=checkFormData(value,8,'float',2)">

js:

//检测输入框数据 value输入框值 length输入整数长度 type输入类型 point小数点后位数

function checkFormData(value,length ,type, point=2) {
    if(value.length==0) return value;
    if(value<0) value = Math.abs(value);
    if(type=='text') {
        if(value.length > length)value = value.slice(0, length);
    } else if(type=='float'){
        value = value.toString();
        if(value.indexOf('.')>=0) {
            let arr = value.split(".");
            var val_int,val_float,p10=1;
            if(arr[1].length>point ||arr[0].length>length) {
                if(arr[0].length>length) {
                    val_int = arr[0].slice(0, length);
                }else {
                    val_int = arr[0];
                }
                if(arr[1].length>point) {
                    val_float = arr[1].slice(0, point);
                }else {
                    val_float = arr[1];
                }
                for (var i=0;i<point;i++) {
                    p10*=10;
                }
                val_float = parseFloat(val_float/p10);
                value = parseFloat(parseInt(val_int) + parseFloat(val_float)).toFixed(point);
            }
        }else{
            if(value.length > length)value = value.slice(0, length);
            value = parseInt(value);
        }
        if(isNaN(value)) value = 0;
    } else if(type=='int'){
        if(value.length > length)value = value.slice(0, length);
        value = parseInt(value);
        if(isNaN(value)) value = 0;

    }

    return value;
}