what is the meaning of parseint in javascript code example

Example: parseint

// parseInt
parseInt("10");//------------ 10
parseInt("10.00");//--------- 10
parseInt("10.33")//--------- 10
parseInt("34 45 66")//------ 34
parseInt("   60   ")//------ 60
parseInt("40 years")//------ 40
parseInt("He was 40")//----- NaN
parseInt("10", 10)//-------- 10
parseInt("010")//----------- 10
parseInt("10", 8)//--------- 8
parseInt("0x10")//---------- 16
parseInt("10", 16)//-------- 16
// parseFloat
parseFloat("10")//-----------10
parseFloat("10.00")//--------10
parseFloat("10.33")//--------10.33
parseFloat("34 45 66")//-----34
parseFloat(" 60 ")//---------60
parseFloat("40 years")//-----40
parseFloat("He was 40");//----NaN
/ mm.mirzaei /