JavaScript validation functions often used to collect 1th/3 page _javascript Tips

We recommend that you collect JavaScript validation function, you will be able to use the next encounter directly
/*
==================================================================

Is null, only the string is judged
Null or 0 long empty, after trim
Isstringnull (String)

==================================================================

*/

function Isstringnull (str) {
if (str = null)
return true;
var trimstr = Trim (str);
if (trimstr.length = 0)
return true;
return false;
}
/*

==================================================================

LTrim (String): Removing space on the left

==================================================================

*/

function LTrim (str) {
var whitespace = new String ("\t\n\r");
var s = new String (str);

if (Whitespace.indexof (S.charat (0))!=-1) {
var j = 0, i = s.length;
while (J < i && Whitespace.indexof (S.charat (j))!=-1) {
j + +;
}
s = s.substring (j, I);
}
return s;
}


/*

==================================================================

RTrim (String): Remove the space on the right

==================================================================

*/

function RTrim (str) {
var whitespace = new String ("\t\n\r");
var s = new String (str);
if (Whitespace.indexof (S.charat (s.length-1))!=-1) {
var i = s.length-1;
while (i >= 0 && whitespace.indexof (s.charat (i))!=-1) {
i--;
}
s = s.substring (0, i + 1);
}
return s;
}


/*

==================================================================

Trim (String): Remove before and after spaces

==================================================================

*/

function Trim (str) {
Return RTrim (LTrim (str));
}

/*

==================================================================

Isoutoflength (String,int): Determines whether the string is longer than length, Chinese is 2 characters

==================================================================

*/

function Isoutoflength (str, len) {
var strlength = 0;
for (var i = 0; i < str.length; i++) {
if (Str.charcodeat (i) > 256) {
strlength++;
}
strlength++;
if (Strlength > Len) {
return true;
}
}
return false;
}

Current 1/3 page 123 Next read the full text