Regular expression method
function checkRate (input)
{
var re = /^[0-9] .?[0-9]*$/; //Judge whether the string is a number//Judge a positive integer/^[1-9 ] [0-9]*]*$/
if (!re.test(input.rate.value))
{
alert("Please enter a number (eg: 0.02)");
input.rate.focus();
return false;
}
}
The following is how to write the ordinary function
function BASEisNotNum(theNum)
{
//Determine whether it is a number
if (BASEtrim(theNum)=="")
return true;
for(var i=0;ioneNum=theNum.substring(i, i 1);
if (oneNum<"0" || oneNum>"9")
return true;
}
return false;
}
function BASEisNotInt(theInt)
{
//Determine whether it is an integer
theInt=BASEtrim(theInt);
if ((theInt.length>1 && theInt.substring(0,1)=="0") | | BASEisNotNum(theInt)){
return true;
}
return false;
}
function BASEisNotFloat(theFloat)
{
//Determine whether it is a floating point number
len=theFloat.length;
dotNum=0;
if (len==0)
return true;
for(var i=0;ioneNum=theFloat.substring(i,i 1);
if (oneNum==".")
dotNum ;
if ( ((oneNum<"0" || oneNum>"9") && oneNum!=".") || dotNum>1)
return true;
}
if (len>1 && theFloat.substring(0,1)=="0"){
if (theFloat.substring(1,2)!=".")
return true;
}
return false;
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