1 /** 2  * 限制文本框只能输入数字 3  * @constructor 4  */ 5 function validateDigitsOnly(evt) { 6     var e = evt || window.event, 7         key = e.keyCode || e.which; 8  9     if (10 // Backspace, Tab, Enter, Esc, Delete11         key == 8 || key == 9 || key == 13 || key == 27 || key == 46 ||12 // Ctrl + A13         (key == 65 && event.ctrlKey === true) ||14 // Home, End, 四个方向键15         key >= 35 && key <= 40) {16         return;17     }18 19     if (e.shiftKey || e.altKey || e.ctrlKey) {20         return false;21     }22 23     var el = e.target || e.srcElement,24 // 最大数字长度25         nl = el.getAttribute("data-numbers") || 15,26 // 最大小数长度27         dl = el.getAttribute("data-decimals") || 2,28         val = el.value,29 // "." 位置30         dotIndex = val.indexOf("."),31         rng = caret.call(el),32 // 光标在"."左边33         rLeft = rng.end <= dotIndex,34 // 光标在"."右边35         rRight = rng.begin > dotIndex;36 37     if (38 // 数字39         key >= 48 && key <= 57 ||40 // 数字键盘输入的数字41         key >= 96 && key <= 105) {42         if (validateValue(dotIndex, val, rLeft, rRight, nl, dl))43             return;44 45 // 选中部分文本再做一次处理46         val = val.substring(0, rng.begin) + val.substring(rng.end);47         dotIndex = val.indexOf(".");48         if (validateValue(dotIndex, val, rLeft, rRight, nl, dl))49             return;50     }51     else if (52 // ".", ","53         (key == 190 /*|| key == 188*/ ||54 // 数字键盘上的 ".", ","55             key == 110/*|| key == 109*/) &&56 // 允许输入小数57         dl > 0) {58         if (59 // 未输入".", 且输入的位置后面的小数位数未达到上限60             dotIndex == -1 && (rng.end == val.length || val.substring(rng.end).length <= dl) ||61 // 输过".", 且选中部分文本包含"."62             dotIndex > -1 && rng.begin <= dotIndex && dotIndex < rng.end)63             return;64     }65 66     return false;67 }68 69 // 验证输入的值70 function validateValue(dotIndex, val, rLeft, rRight, nl, dl) {71     if (72 // 未输入过"."73         dotIndex == -1 && val.length < nl ||74 // 光标位置在"."之前75         rLeft && val.substring(0, dotIndex).length < nl ||76 // 光标在"."之后且未达到小数上限77         rRight && val.substring(dotIndex + 1).length < dl)78         return true;79     return false;80 }81 82 // 获取光标位置83 function caret() {84     var begin, end;85     if (this.setSelectionRange) {86         begin = this.selectionStart;87         end = this.selectionEnd;88     } else if (document.selection && document.selection.createRange) {89         var range = document.selection.createRange();90         begin = 0 - range.duplicate().moveStart(‘character‘, -100000);91         end = begin + range.text.length;92     }93     return { begin: begin, end: end };94 }